A transient error, also known as a transient fault, has an underlying cause that soon resolves itself. An occasional cause of transient errors is when the Azure system quickly shifts hardware resources to better load-balance various workloads. Most of these reconfiguration events finish in less than 60 seconds. During this reconfiguration time span, you might have issues with connecting to your database in SQL Database. Applications that connect to your database should be built to expect these transient errors. To handle them, implement retry logic in their code instead of surfacing them to users as application errors.

This issue was related to a recent Azure DB infrastructure migration activity. They have upgraded some of their clusters to newer hardware across all the regions, and our database was part o that migration. This might be the reason for these issues, and they have suggested implementing a retry mechanism for error code 40613, and now we are not receiving this type of error.

Action : You don't need to do anything other than retry logic.

A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - The specified network name is no longer available.)

A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

System.Data.SqlClient.SqlException (0x80131904): A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

System.Data.SqlClient.SqlException (0x80131904): The service has encountered an error processing your request. Please try again. Error code 9001. The service has encountered an error processing your request. Please try again. Error code 9001. The service has encountered an error processing your request. Please try again. Error code 3314. A severe error occurred on the current command. The results, if any, should be discarded.

More detail : https://learn.microsoft.com/en-us/azure/azure-sql/database/troubleshoot-common-connectivity-issues?view=azuresql