According to your description, I move the question to the related forums (SQL HA and DR). It is appropriate and more experts will assist you.
A service principal name (SPN) is the name by which a client uniquely identifies an instance of a service. If you are using Kerberos, we need to make sure that the service principal names are correct in Active Directory and that SQL Server is registering
The SQL Server Network Interface library successfully registered the Service Principal Name (SPN) for the SQL Server service.You can run the following SETSPN command: setspn -A MSSQLSvc/<FQDN> <SQL_Service_Account>
For example, if MySQLServer.MyDomain.com is running under the domain user account SQLSVC, where MySQLServer.MyDomain.com is the name of the instance of SQL Server
that is clustered, run the following command: setspn -A MSSQLSvc/MySQLServer.MyDomain.com SQLSVC