Failure when trying to swap Azure app service slots

Question

Failure when trying to swap Azure app service slots

David John 0

I am trying to swap from our staging deployment slot to production slot.

But I am consistently getting an error on the Azure portal. This has not happened before.

I have stopped, started all slots.

Checked all configuration but still getting an error.

After going to diagnostics when trying to create a support ticked, I see the error below in the hosting code.

Anyone have any idea how to fix?

Thank you.

Swap failed. Details: System.IO.IOException: The user name or password :[PASSWORD] incorrect. at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) at System.IO.Directory.InternalCreateDirectory(String fullPath, String path, Object dirSecurityObj, Boolean checkHost) at System.IO.Directory.InternalCreateDirectoryHelper(String path, Boolean checkHost) at Microsoft.Web.Hosting.Administration.WebCloudController.WriteDiagnosticsSettingsFile(SiteManager siteManager, Site site, ScmDiagnosticsSettings scmDiagnosticsSettings) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 10691 at Microsoft.Web.Hosting.Administration.WebCloudController.WriteDiagnosticsSettingsFile(SiteManager siteManager, Site site, ScmDiagnosticsSettings scmDiagnosticsSettings) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 10729 at Microsoft.Web.Hosting.Administration.WebCloudController.UpdateSiteLogsConfigInternal(String subscriptionName, String webspaceName, String name, SiteLogsConfig siteLogsConfig, Boolean preservingSiteLogsConfig, String requestIdOfOrginatingCall, String clientRequestIdOfOriginatingCall, String correlationRequestIdOfOriginatingCall) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 10640 at Microsoft.Web.Hosting.Administration.WebCloudController.PreserveDefaultStickySettings(String subscriptionName, String webspaceName, Site site, WebSite siteRecord, SlotConfig slotConfig, String requestIdOfOrginatingCall, String clientRequestIdOfOriginatingCall, String correlationRequestIdOfOriginatingCall, Boolean applyManagedIdentitySettingsToSiteConfig) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 20605 at Microsoft.Web.Hosting.Administration.WebCloudController.ApplySlotConfigInternal(String subscriptionName, String webspaceName, Site currentSite, Site targetSite, SlotConfigNames slotConfigNames, SwapOptions swapOptions) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 20068 at Microsoft.Web.Hosting.Administration.WebCloudController.SwapSiteSlots(String subscriptionName, String webspaceName, String name, String command, String targetSlotName, SwapOptions swapOptions, Boolean authZOnBackgroundTask, Nullable`1 operationId) in //src/Hosting/AdministrationService/Microsoft.Web.Hosting.Administration/Controllers/WebCloudController.cs:line 17403

SUNOJ KUMAR YELURU 15,496 Reputation points MVP

2025-07-01T04:25:08.06+00:00

Hello @David John

The most likely cause of the "System.IO.IOException: The user name or password :[PASSWORD] incorrect" error during the slot swap is an authentication issue related to application settings, connection strings, or diagnostic settings. The solution involves carefully reviewing and correcting the credentials in these settings, ensuring the App Service has the necessary permissions to access any associated storage accounts, and restarting the App Service.

Step 1: Investigate Application Settings and Connection Strings

The error message indicates an authentication problem. The first step is to check all application settings and connection strings in both the staging and production slots.

Navigate to the Azure Portal: Open the Azure portal and go to your App Service.

Check Application Settings:

Go to "Configuration" under "Settings" for both the staging and production slots.

Review all application settings, paying close attention to any settings that involve usernames, passwords, or connection strings.

Ensure that all credentials are correct and up-to-date.

Check Connection Strings:

In the same "Configuration" section, check the "Connection strings" tab.

Verify that all connection strings are accurate and that the associated databases or services are accessible with the provided credentials.

Update Incorrect Credentials: If you find any incorrect or outdated credentials, update them and save the changes. Restart the App Service after making changes.

Step 2: Review Diagnostic Settings

The error message specifically mentions WriteDiagnosticsSettingsFile, indicating a problem with writing diagnostic settings.

Navigate to Diagnostic Settings: In the Azure portal, go to your App Service and then to "Diagnostic settings" under "Monitoring".

Examine Log Streaming Settings: Check the settings for "App Service logs" and "Web server logs". Ensure that the storage account configured for these logs is accessible and that the App Service has the necessary permissions.

Check Storage Account Access:

If you are using a storage account for diagnostics, verify that the App Service has the necessary permissions to write to the storage account. This can be done using Managed Identity or by ensuring the connection string is valid and has the appropriate access rights.

Reconfigure Diagnostic Settings: If you suspect a problem with the diagnostic settings, try disabling and re-enabling them. This can sometimes resolve configuration issues.

Step 3: Verify Storage Account Permissions (If Applicable)

If your diagnostic settings use a storage account, ensure the App Service has the correct permissions.

Identify the Storage Account: Determine which storage account is being used for diagnostic logs.

Check Access Control (IAM):

Go to the storage account in the Azure portal.

Navigate to "Access control (IAM)".

Add a role assignment for the App Service's Managed Identity (if used) or ensure that the App Service's identity has the "Storage Blob Data Contributor" role. If not using Managed Identity, ensure the storage account's access keys are valid in the App Service's configuration.

Test Storage Account Access: You can use the Azure Storage Explorer to test the connection to the storage account using the same credentials configured in the App Service.

Step 4: Restart and Re-apply Configuration

Sometimes, a simple restart can resolve transient issues.

Restart the App Service: In the Azure portal, go to your App Service and click "Restart". Do this for both the staging and production slots.

Re-apply Configuration: After restarting, review the application settings, connection strings, and diagnostic settings to ensure they are correctly configured. Save any changes.

Attempt the Swap Again: Try swapping the slots again to see if the issue has been resolved.

If this answers your query, do click Accept Answer and Up-Vote for the same. And, if you have any further query do let us know.
David John 0 Reputation points

2025-07-01T07:09:10.9966667+00:00

Thank you Sunoj for responding.
I have checked all the connections and they are valid.

The issue seems to be changing the diagnostics settings. Via the portal when I click on Monitoring > App Service Logs > Application Logging (Blob) and enable it, when I hit Save it errors. The same error as in the main article around usernmae/password.

The connection string to storage is valid.

The configuration just will not save to the app service.

The app service identity is fine.

It looks to me to be an underlying platform issue with the win32 identity check??
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-01T08:06:04.0666667+00:00
Hi David John,

This error usually happens when the platform cannot write diagnostic settings to the storage account due to one of the following reasons:

The App Service doesn't have proper permissions to write to the storage account (even if the connection string appears valid).

The storage connection string in the configuration uses outdated keys or has formatting issues.

The issue lies within Azure internal platform identity checks (Win32-level) when trying to validate credentials used for diagnostic writing, especially in Windows-based App Services.

It seems in your case, it may be the third, a platform-level identity failure, which is rare but can happen if the internal diagnostic module can't establish the correct user context to access Blob storage.

1: Use Managed Identity for Diagnostic Logs:

Switch from using storage keys in the connection string to Managed Identity-based access. Here's how:

Assign Permissions:

Go to your Storage Account in Azure Portal

Navigate to Access Control (IAM)

Assign the App Service’s System-Assigned Managed Identity the Storage Blob Data Contributor role

Configure Diagnostics with MSI:

In App Service: Go to Monitoring => Diagnostic Settings

Create a new setting (if needed) and select the storage account

Ensure "Use system-assigned managed identity" is selected Enable diagnostics logging in Azure App Service Use managed identity to access Azure Blob Storage

2: Regenerate and Reconnect Storage Key (if not using MSI)

If you're not using Managed Identity:

Go to the Storage Account => Access Keys

Regenerate the key used in your App Service

Update the connection string in both staging and production slot configs

Save the config, restart the App Service, and retry enabling logs Configure storage account for diagnostic logs

Temporary Workaround – Disable Blob Logging, if diagnostics logging to Blob is not a strict requirement:

Disable the Application Logging (Blob) temporarily from both slots

Perform the slot swap

Then reconfigure the logging

Hope this helps, if you have any further concerns or queries, please feel free to reach out to us.
David John 0 Reputation points

2025-07-02T00:42:34.85+00:00

Thank you @Bhargavi Naragani for the response.

I have tried all that you said - I removed all diagnostic settings in the environment variables. For both staging, production and bugfix slots.

I restarted them all.

But I still get the same error.

Is there something else I can try?

Thank you
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T01:32:24.97+00:00
Hi David John,

It seems like the error still persists during the slot swap, it suggests that this is now not a misconfiguration on your end, but more likely a platform-level issue with App Service’s diagnostics subsystem, especially related to writing settings via the underlying identity mechanism.

Attempt to completely disable App Service Diagnostics at the platform level to see if that allows the swap:

Go to each slot (staging, production, bugfix):

Navigate to Monitoring => App Service Logs, set all the below to Off:

Application Logging (Filesystem & Blob)

Web Server Logging

Detailed Error Messages

Failed Request Tracing Click Save after disabling all logs.

Now go to Diagnostic settings under Monitoring, delete any custom diagnostic setting entries that may point to a Log Analytics workspace or storage account.

Restart all the slots again after saving.

Try the swap once more.

If the swap succeeds after these steps, that will confirm the issue is isolated to diagnostic write operations during the swap process. Manage diagnostic settings in Azure

At this point, if you're still encountering the same System.IO.IOException: The user name or password is incorrect during slot swap, this is very likely an internal App Service platform issue, possibly related to a corrupted or stuck diagnostics state behind the scenes.

We recommend opening a Microsoft Support Request to allow:

Access the underlying hosting environment

Review platform-level logs

Reset or patch the diagnostics module if needed Create Azure Support Reques
David John 0 Reputation points

2025-07-02T01:45:04.3433333+00:00

@Bhargavi Naragani It appears I can only create QA tickets here as my plan is Developer.
Can I submit this issue and get it looked at here?
Or do I need to upgrade to Standard Support?
This needs looking into as it is holding up deployment.
Thanks.
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T01:56:37.0733333+00:00
David John,

Even on the Developer plan, you can open a free support request for platform faults (like service issues, quotas, deployment failures):

Go to: Azure Portal – Help + support

Choose Issue Type: Technical

Under Problem type, choose: App Service Deployment or Slot Swap Failure

For Support Plan, select Developer, the portal will show you if it's eligible for a free support escalation based on category.

If this route is blocked, move to Option 2.

If this is a production-blocking issue and needs urgent backend engineering intervention, upgrading to the Standard support plan may be the quickest route.
David John 0 Reputation points

2025-07-02T02:34:37.65+00:00

@Bhargavi Naragani Every time I try to create a support request I get shown the 'View Solution' page and all I get is the ability to 'Open Solution Page'???
Or Prioritized support on Microsoft Q&A.
Nothing to submit a technical request...
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T18:10:06.6866667+00:00
Hi David John,

Your developer plan limits your ability to open a technical ticket.

Only Standard, Professional Direct, and Premier plans allow you to open technical support tickets.

If the issue is blocking production and you need a guaranteed technical response, upgrading to the Standard support plan is the most direct option.

You can do it from Azure Portal:

Go to: https://portal.azure.com

Search for “Support plans”

Open the page and choose “Upgrade”

Select Standard or Professional Direct
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-03T09:05:49.5633333+00:00

Hi David John,
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
David John 0 Reputation points

2025-07-03T22:47:17.14+00:00

Hi @Bhargavi Naragani ,

Thanks for checking in. I have submitted a technical support request and will hopefully get it sorted. It appears to be a Azure platform thing.

Thank you for your help! :)
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-04T01:07:16.2566667+00:00

Hi David John,
We received your feedback that the answer provided on the thread was not helpful. Kindly let us know what we could have done better to improve the answer and make your engagement experience good. We are here to help you and strive to make your experience better and greatly value your feedback.

Thank you for taking time to share your feedback and solution. If you wish, you may re-surveying for the engagement you received on the thread. Your feedback is very important to us.

Looking forward to your reply. Much appreciate your feedback!

Your answer

David John 0 Reputation points

2025-07-01T07:09:10.9966667+00:00

Thank you Sunoj for responding.
I have checked all the connections and they are valid.

The issue seems to be changing the diagnostics settings. Via the portal when I click on Monitoring > App Service Logs > Application Logging (Blob) and enable it, when I hit Save it errors. The same error as in the main article around usernmae/password.

The connection string to storage is valid.

The configuration just will not save to the app service.

The app service identity is fine.

It looks to me to be an underlying platform issue with the win32 identity check??
David John 0 Reputation points

2025-07-02T00:42:34.85+00:00

Thank you @Bhargavi Naragani for the response.

I have tried all that you said - I removed all diagnostic settings in the environment variables. For both staging, production and bugfix slots.

I restarted them all.

But I still get the same error.

Is there something else I can try?

Thank you
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T01:32:24.97+00:00

Hi David John,

It seems like the error still persists during the slot swap, it suggests that this is now not a misconfiguration on your end, but more likely a platform-level issue with App Service’s diagnostics subsystem, especially related to writing settings via the underlying identity mechanism.

Attempt to completely disable App Service Diagnostics at the platform level to see if that allows the swap:

Go to each slot (staging, production, bugfix):

Navigate to Monitoring => App Service Logs, set all the below to Off:

Application Logging (Filesystem & Blob)

Web Server Logging

Detailed Error Messages

Failed Request Tracing Click Save after disabling all logs.

Now go to Diagnostic settings under Monitoring, delete any custom diagnostic setting entries that may point to a Log Analytics workspace or storage account.

Restart all the slots again after saving.

Try the swap once more.

If the swap succeeds after these steps, that will confirm the issue is isolated to diagnostic write operations during the swap process. Manage diagnostic settings in Azure

At this point, if you're still encountering the same System.IO.IOException: The user name or password is incorrect during slot swap, this is very likely an internal App Service platform issue, possibly related to a corrupted or stuck diagnostics state behind the scenes.

We recommend opening a Microsoft Support Request to allow:

Access the underlying hosting environment

Review platform-level logs

Reset or patch the diagnostics module if needed Create Azure Support Reques
David John 0 Reputation points

2025-07-02T01:45:04.3433333+00:00

@Bhargavi Naragani It appears I can only create QA tickets here as my plan is Developer.
Can I submit this issue and get it looked at here?
Or do I need to upgrade to Standard Support?
This needs looking into as it is holding up deployment.
Thanks.
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T01:56:37.0733333+00:00

David John,

Even on the Developer plan, you can open a free support request for platform faults (like service issues, quotas, deployment failures):

Go to: Azure Portal – Help + support

Choose Issue Type: Technical

Under Problem type, choose: App Service Deployment or Slot Swap Failure

For Support Plan, select Developer, the portal will show you if it's eligible for a free support escalation based on category.

If this route is blocked, move to Option 2.

If this is a production-blocking issue and needs urgent backend engineering intervention, upgrading to the Standard support plan may be the quickest route.
David John 0 Reputation points

2025-07-02T02:34:37.65+00:00

@Bhargavi Naragani Every time I try to create a support request I get shown the 'View Solution' page and all I get is the ability to 'Open Solution Page'???
Or Prioritized support on Microsoft Q&A.
Nothing to submit a technical request...
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-02T18:10:06.6866667+00:00

Hi David John,

Your developer plan limits your ability to open a technical ticket.

Only Standard, Professional Direct, and Premier plans allow you to open technical support tickets.

If the issue is blocking production and you need a guaranteed technical response, upgrading to the Standard support plan is the most direct option.

You can do it from Azure Portal:

Go to: https://portal.azure.com

Search for “Support plans”

Open the page and choose “Upgrade”

Select Standard or Professional Direct
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-03T09:05:49.5633333+00:00

Hi David John,
We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
David John 0 Reputation points

2025-07-03T22:47:17.14+00:00

Hi @Bhargavi Naragani ,

Thanks for checking in. I have submitted a technical support request and will hopefully get it sorted. It appears to be a Azure platform thing.

Thank you for your help! :)
Bhargavi Naragani 6,535 Reputation points Microsoft External Staff Moderator

2025-07-04T01:07:16.2566667+00:00

Hi David John,
We received your feedback that the answer provided on the thread was not helpful. Kindly let us know what we could have done better to improve the answer and make your engagement experience good. We are here to help you and strive to make your experience better and greatly value your feedback.

Thank you for taking time to share your feedback and solution. If you wish, you may re-surveying for the engagement you received on the thread. Your feedback is very important to us.

Looking forward to your reply. Much appreciate your feedback!

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Failure when trying to swap Azure app service slots

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