Web app path mappings for one app service doesn't work whereas others configured the same do

Question

Web app path mappings for one app service doesn't work whereas others configured the same do

Paul Sloman 0

I have a few app services, each have an Azure File Storage mounted, and then virtual directories mapped to that mount. This is working fine in two UK setups, works on my original Canadian service, but I'm now adding a second app in Canada, pointing to the same file storage and its not working.

I can log into the new app service and navigate to c:\mounts{store} and can see the files fine, but when I try to use a web browser or postman to get one of these files it comes back with 404 "The resource you are looking for has been removed, had its name changed, or is temporarily unavailable."

As far as I can see the config for all apps are the same, they all run the same code.

Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T04:55:55.7166667+00:00

Hi @Paul Sloman ,

Check if the virtual directory path mapping is correctly configured under 'Configuration → Path Mappings' in Azure Portal. Also, verify that WEBSITE_ENABLE_APP_SERVICE_STORAGE is set to true in environment variables.
Paul Sloman 0 Reputation points

2025-03-18T05:06:24.36+00:00

The Path Mappings is set the same as three other web apps that work perfectly. None of the others have the WEBSITE_ENABLE_APP_SERVICE_STORAGE set. I tried on this app and it made no difference. I Googled this and it sounded like it should have been WEBSITES_ENABLE_APP_SERVICE_STORAGE so I tried that too and still nothing.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T05:22:52.1033333+00:00

Since path mappings are identical and enabling WEBSITE_ENABLE_APP_SERVICE_STORAGE didn’t help, try Verifying that App Service has proper permissions to the Azure File Storage by ensuring the app's managed identity has Storage File Data SMB Share Contributor or Storage File Data Reader role assigned.
Paul Sloman 0 Reputation points

2025-03-18T05:41:13.5033333+00:00

Hasn't made a difference. I think we might be going down the wrong road. I can log into the console of the app and see the files under c:\mounts so I don't think its a permissions thing for the app to get to the files.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T06:20:02.5666667+00:00

Can you confirm what framework your app is using (IIS, ASP.NET Core, etc.)?
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-20T05:35:51.92+00:00

Hi @Paul Sloman ,

Just checking in to see if your issue has been resolved. If you have any further updates on this issue, please feel free to post back.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-20T06:19:03.7733333+00:00
Hi @Paul Sloman ,

Can you please check ,

Make sure the virtual directory is set up correctly in IIS (if you're using IIS). You can check this by going to IIS Manager → Sites → Your App Service → Virtual Directories. Ensure that the virtual directory points to c:\mounts{store} and has the right permissions.

Make sure your virtual directory is set up correctly in IIS (if you're using it). You can check this in IIS Manager by going to Sites → Your App Service → Virtual Directories. Just confirm that the virtual directory is pointing to c:\mounts{store} and has the right permissions.

Confirm if WEBSITE_CONTENTOVERRIDE is set. If this setting is present, it may be overriding your path mappings. Hope it helps.

1 answer

Your answer

Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T04:55:55.7166667+00:00

Hi @Paul Sloman ,

Check if the virtual directory path mapping is correctly configured under 'Configuration → Path Mappings' in Azure Portal. Also, verify that WEBSITE_ENABLE_APP_SERVICE_STORAGE is set to true in environment variables.
Paul Sloman 0 Reputation points

2025-03-18T05:06:24.36+00:00

The Path Mappings is set the same as three other web apps that work perfectly. None of the others have the WEBSITE_ENABLE_APP_SERVICE_STORAGE set. I tried on this app and it made no difference. I Googled this and it sounded like it should have been WEBSITES_ENABLE_APP_SERVICE_STORAGE so I tried that too and still nothing.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T05:22:52.1033333+00:00

Since path mappings are identical and enabling WEBSITE_ENABLE_APP_SERVICE_STORAGE didn’t help, try Verifying that App Service has proper permissions to the Azure File Storage by ensuring the app's managed identity has Storage File Data SMB Share Contributor or Storage File Data Reader role assigned.
Paul Sloman 0 Reputation points

2025-03-18T05:41:13.5033333+00:00

Hasn't made a difference. I think we might be going down the wrong road. I can log into the console of the app and see the files under c:\mounts so I don't think its a permissions thing for the app to get to the files.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-18T06:20:02.5666667+00:00

Can you confirm what framework your app is using (IIS, ASP.NET Core, etc.)?
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-20T05:35:51.92+00:00

Hi @Paul Sloman ,

Just checking in to see if your issue has been resolved. If you have any further updates on this issue, please feel free to post back.
Sirra Sneha 310 Reputation points Microsoft External Staff

2025-03-20T06:19:03.7733333+00:00

Hi @Paul Sloman ,

Can you please check ,

Make sure the virtual directory is set up correctly in IIS (if you're using IIS). You can check this by going to IIS Manager → Sites → Your App Service → Virtual Directories. Ensure that the virtual directory points to c:\mounts{store} and has the right permissions.

Make sure your virtual directory is set up correctly in IIS (if you're using it). You can check this in IIS Manager by going to Sites → Your App Service → Virtual Directories. Just confirm that the virtual directory is pointing to c:\mounts{store} and has the right permissions.

Confirm if WEBSITE_CONTENTOVERRIDE is set. If this setting is present, it may be overriding your path mappings. Hope it helps.

Answer 1

Paul Sloman 0

Nothing you've suggested has worked so in the end I used a different file storage and that has started working properly. It worries me that we've only just moved to Azure and we're getting these sorts of anomalies where a second setup is configured exactly the same as another and they behave differently and the only way to fix it that I've found is to start again.

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Web app path mappings for one app service doesn't work whereas others configured the same do

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