Health of 'Re-protection server' on ASR replication appliance is critical as latest heartbeat is missing.

@Kale, Ashish Thank you for posting your query on the Microsoft Q&A platform. Happy to assist you!

From the description I understand that you noticed health critical alerts for re-protection server. It looks like you are experiencing an issue with the "Re-protection server" on your Azure Site Recovery (ASR) replication appliance. The error message indicates that the server is unable to communicate with Site Recovery services in Azure, and that one or more required service principal (SPN) in Azure Active Directory is no longer available.

Here are some steps you can take to troubleshoot this issue:

1. Check the status of the "Re-protection server" in the ASR portal. If the server is shown as "Critical", this indicates that there is a problem with the server or the connection to the server.
2. Check the network connectivity between the ASR replication appliance and the "Re-protection server". Make sure that the server is accessible from the replication appliance and that there are no network issues that could be causing the problem.
3. Check the Azure Active Directory (AAD) to ensure that the required service principal (SPN) is available. If the SPN is missing, you can create a new one by following the steps in the Microsoft documentation on Create an Azure AD application and service principal that can access resources.
4. Check the permissions of the SPN in Azure. Make sure that the SPN has the necessary permissions to access the Site Recovery services in Azure.
5. Restart the "Re-protection server" and see if this resolves the issue. If the server is a virtual machine, you can try restarting the VM. If the server is a physical machine, you can try restarting the server or the services that are responsible for the heartbeat.
6. If the issue persists, you may need to contact Azure support for assistance. You can submit a support case through the Azure portal and provide the error message and any other relevant information.

Hope this helps! Let me know if you have any other questions or if there is anything else I can assist you with.

Tried all steps, still no luck.