SSPI handshake failed with error code 0x8009030c

To resolve the error of  SSPI handshake failed. 

EXEC xp_readerrorlog     0,    1,    'SSPI handshake failed' 

The above code produces the Client IP address..

To detect the machine name type nslookup "IPaddress or Machine name" to get the desired result

Check the authentication that sql is currently running under .

SELECT net_transport, auth_scheme FROM sys.dm_exec_connections WHERE session_id = @@spid

If that authentication shows NTLM then consider the below troubleshooting methods 

Look for the current and archive logs to identify the SPN error as  per below

EXEC xp_readerrorlog     1,    1,    'SPN' 

The success code 

The error code