This page lists known issues with Cloud SQL for SQL Server, along with ways you can avoid or recover from these issues.
Instance connection issues
Expired SSL/TLS certificates
If your instance is configured to use SSL, go to the Cloud SQL Instances page in the Cloud Console and open the instance. Open its Connections page and make sure that your server certificate is valid. If it has expired, you must add a new certificate and rotate to it. Learn more.
Cloud SQL Proxy version
If you are connecting using the Cloud SQL Proxy, make sure you are using the most recent version. For more information, see Keeping the Cloud SQL Proxy up to date.
Not authorized to connect
If you try to connect to an instance that does not exist in that project, the error message only says that you are not authorized to access that instance.
If the database version of your SQL Server instance is SQL Server 2017 Express:
If you specify a flag when you create a new instance, creation of the instance fails.
You cannot set database flags on an existing instance.
Long-running operations cannot be cancelled or stopped
When you start a long-running operation, such as an import or export operation, you cannot stop the operation before it completes. In addition, only one operation can run against an instance at at time.
For this reason, make sure you do not need to do other work on an instance when you start a long-running operation.
Instance names cannot be reused immediately after instance deletion
After you delete an instance, you cannot immediately reuse the instance name, because Cloud SQL reserves that name for a few days. If you need to create and delete instances with the same name, consider using a timestamp as part of the name to avoid name conflicts.