SQL Connection Error

Had this issue today and could not find anything about it.

SSPI handshake failed with error code 0x80090346 state 45…

Error 17805 Severity 20 State 45

Login failed. ┬áThe login is from an untrusted domain…

Error 18452 Severity 14 State 1

The issue was that SQL Server 2012 was configured as Extended Protection = Allow but extended protection was not enabled on the server.

HKLM\SYSTEM\CurrentControlSet\Control\Lsa\SuppressExtendedProtection did not exist.

Setting Extended Protection = Off fixed the issue.