Azure VM backup is getting failed

Question

Azure VM backup is getting failed

Mohd Shahid Firoz Khan 20

Hi Team,

We have one window server 2012 R2 and SQL is also running on that server.

The azure backup is getting failed on daily basis with the error.

Error Code:ExtensionSnapshotFailedNoNetwork

Error: Snapshot operation failed due to no network connectivity on the virtual machine.

I tried my best and refer some azure documents but no luck.

1 answer

Your answer

Answer 1

Marcin Policht 50,495 MVP Volunteer Moderator

As per https://learn.microsoft.com/en-us/azure/backup/backup-azure-troubleshoot-vm-backup-fails-snapshot-timeout

ExtensionSnapshotFailedNoNetwork - Snapshot operation failed due to no network connectivity on the virtual machine

Error code: ExtensionSnapshotFailedNoNetwork Error message: Snapshot operation failed due to no network connectivity on the virtual machine

After you register and schedule a VM for the Azure Backup service, Backup starts the job by communicating with the VM backup extension to take a point-in-time snapshot. Any of the following conditions might prevent the snapshot from being triggered. If the snapshot isn't triggered, a backup failure might occur. Complete the following troubleshooting step, and then retry your operation:

The snapshot status can't be retrieved, or a snapshot can't be taken

The snapshot status can't be retrieved, or a snapshot can't be taken

The VM backup relies on issuing a snapshot command to the underlying storage account. Backup can fail either because it has no access to the storage account, or because the execution of the snapshot task is delayed.

Solution for this issue

The following conditions might cause the snapshot task to fail:

Expand table

Cause	Solution
The VM status is reported incorrectly because the VM is shut down in Remote Desktop Protocol (RDP).	If you shut down the VM in RDP, check the portal to determine whether the VM status is correct. If it's not correct, shut down the VM in the portal by using the Shutdown option on the VM dashboard.
The VM status is reported incorrectly because the VM is shut down in Remote Desktop Protocol (RDP).	If you shut down the VM in RDP, check the portal to determine whether the VM status is correct. If it's not correct, shut down the VM in the portal by using the Shutdown option on the VM dashboard.
The VM can't get the host or fabric address from DHCP.	DHCP must be enabled inside the guest for the IaaS VM backup to work. If the VM can't get the host or fabric address from DHCP response 245, it can't download or run any extensions. If you need a static private IP, you should configure it through the Azure portal or PowerShell and make sure the DHCP option inside the VM is enabled. Learn more about setting up a static IP address with PowerShell.

If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.

hth

Marcin

Mohd Shahid Firoz Khan 20 Reputation points

2025-04-01T17:17:26.2333333+00:00

Hi Marcin,

I have already tried the mentioned step and documents, but it didn't help to fix the issue
Mohd Shahid Firoz Khan 20 Reputation points

2025-04-01T19:51:54.4333333+00:00

The VM is showing below errors.
Marcin Policht 50,495 Reputation points MVP Volunteer Moderator

2025-04-01T20:17:59.29+00:00
Try the following:

Verify VM's network connectivity:

Check if the Network Security Group (NSG) or Firewall rules are blocking outbound traffic.

Allow Azure datacenter IP ranges:

Azure snapshots may require outbound access to certain Azure services.

To allow this, add Azure’s public IP ranges to the NSG or Firewall.

Get the latest Azure datacenter IP ranges here.

Ensure VM can reach Azure Backup and Storage services:

Try accessing Azure Storage services from the VM using:
curl https://www.microsoft.com

If this fails, check the outbound connectivity settings.

If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.

hth

Marcin
Vinod Pittala 3,930 Reputation points Microsoft External Staff Moderator

2025-04-02T07:58:19.0833333+00:00
Hello

This issue can happen due to various reasons,

Scenario 1: Backup failed due to network connectivity issue.

Follow the below steps to resolve the issue.

From the failed Virtual Machine, launch the browser and check if you are able to access any public facing internet site. If not, then there is restrictions on making outbound calls from the impacted VM.

From Virtual Machine properties Settings > Networking > Outbound Port Rule check if there are NSG rules with DENY action. Follow this step-by-step video to use Service Tags to enable access to storage endpoints.

If you are using a HTTP Proxy server to have restrict output bound traffic, then follow these steps to enable access to storage endpoints (Azure Public IP addresses).

If you have firewall and proxy in place, try to whitelist below domains

·[www.msftncsi.com]

*.Microsoft.com

*.WindowsAzure.com

*.microsoftonline.com

*.windows.net

Check if the port 443, 8443 and 80 are not blocked on firewall/proxy/NSG, if blocked open and retry backup operation.

Ensure guest agent is installed and is responsive by following these steps for Windows VM

DHCP must be enabled inside the guest for the IaaS VM backup to work, see the Note mentioned in this article .

If network restrictions cannot be removed from the VM, then Backups can be taken when the VM is shutdown. Create a Backup schedule policy which runs when the VM is shutdown this method can usually be used for VM which are turned-off daily.

Scenario 2: Backup failing due to network restriction on the storage account

When the snapshot call fails for few disks and succeed for rest. This can be due to network restriction to that particular storage account

To resolve this issue, perform the below steps:

Resolve network issues in the VM

For Windows VMs, run the below command in an elevated command prompt to update snapshot method REG ADD "HKLM\SOFTWARE\Microsoft\BcdrAgentPersistentKeys" /v SnapshotMethod /t REG_SZ /d onlyHost /f

Restart WAAgent Service and retry the operation.

Scenario 3: Backup failing because one of the VHD name has got '/' character

Root Cause: Backup failing due to '/' character present in VHD name

How to verify if the failure is caused by this specific root cause? ErrorCode is ExtensionSnapshotFailedNoNetwork and one of the VHD name should have '/' character, which is the path parameter.

Workaround The issue can be mitigated by setting the VM configuration file /etc/azure/vmbackup.conf with the configuration value SnapshotMethod = firstGuestThenHost

REG ADD "HKLM\SOFTWARE\Microsoft\BcdrAgentPersistentKeys" /v SnapshotMethod /t REG_SZ /d firstGuestThenHost /f

Scenario 4: Backup failed due to missing python librarires

symptom for this failure? ErrorCode : ExtensionSnapshotFailedNoNetwork

How to verify if the failure is caused by this specific root cause?

If extension logs contain error logs as below

2020/07/22 12:56:11 AttributeError: 'module' object has no attribute 'HTTPSConnection'

It means that python librarires are missing

workaround:

Workaround is to re-install the pip and libraries. Depending on the distro, use "apt-get", "yum", "zypper"

Below is a sample 2 commands that needs to be executed

zypper install python-pip

pip install httplib

Please follow the recommended steps and let us know the results.

Thanks
Mohd Shahid Firoz Khan 20 Reputation points

2025-04-02T09:14:55.4666667+00:00

Hi Vinod,

in the SG the outbound is already allowed based on service tags toward internet but i have also created the outbound rule to storage account.

i have also created the registry value as you mentioned but it didn't works.
Vinod Pittala 3,930 Reputation points Microsoft External Staff Moderator

2025-04-04T07:51:51.9466667+00:00
Hello Mohd Shahid Firoz Khan,

Have you tried opening the browser from the VM to see if you can access any public-facing internet sites? If you are unable to access any public sites, it indicates that your VM has an internet connection issue. In this case, please work with your internal network team to resolve it.

Additionally, please check the proxy settings on the VM by following these steps:

Go to Control Panel -> Network and Internet -> Internet Options.

Click on the Connections tab.

Look for LAN settings.

Uncheck the box if you use a proxy server for LAN.

Click OK.

Please try the above steps and let us know the results.

If you find this comment helpful, please click "Upvote."

Thanks.
Vinod Pittala 3,930 Reputation points Microsoft External Staff Moderator

2025-04-07T07:39:40.59+00:00

Hello Mohd Shahid Firoz Khan,

I hope you had the chance to review the recommendation I provided.

Could you please let us know if it was helpful? If you have any questions or encounter any issues, please don't hesitate to reach out. We are committed to resolving your concerns as a priority.

Thank you!
Vinod Pittala 3,930 Reputation points Microsoft External Staff Moderator

2025-04-10T06:02:46.06+00:00

Hello Mohd Shahid Firoz Khan,

I just wanted to check if the above provided solution worked for you or if you need any further assistance?

Please feel free to let us know, as we are always here to help whenever you need us.

Additionally, if you have a moment, please do upvote it if the information provided has been helpful. This can be beneficial to other community members and would be greatly appreciated.

Thank you.

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Azure VM backup is getting failed

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