Many times setting up servers you’ll get the following.
SSPI handshake failed with error code 0x8009030c, state 14 while establishing a connection with integrated security; the connection has been closed. Reason: AcceptSecurityContext failed. The operating system error code indicates the cause of failure. The logon attempt failed
A few things to keep in mind.
#1 – Is the SPN set properly on SQL. (Done in AD).
#2 – Is Delegation configured on the application? (Done in AD).
Simply put this error can indicate a kerberos error (remember NTLM cannot do delegation).