> Did you try SQL Server IP address instead of server name in the DSN (for troubleshooting)?

I did and still received the error message. I also tried named pipes this morning but still could not log in.

I have just now tried another route of experimentation:

I've tried to modify and test the connection under a different user account. In this case the domain administrator account (overkill I know but it sometimes makes sense, to me, to start at the top).

The administrator account can modify and connect through the DSN without issue! It must be that the domain is unable to verify the usual user's account. As far as I have learnt over the last couple of days, that could cause the "Cannot Generate SSPI Context" message.