With an accompanying error in the log
Login failed for user ‘MyAccount’. [CLIENT: ]
Error: 18456, Severity: 14, State: 11.

Very strange, I thought to myself. Turns out I had added my account to the local administrator’s group and not created a Login on the SQL Server. (It also appears I missed a step on my server checklist, as I normally remove the BuiltinAdministrators group, but who is keeping score?)

I create the Login, and specified the group, and I was good to go.

CREATE LOGIN [DomainAccount] FROM WINDOWS;
EXEC sp_addsrvrolemember [DomainAccount], ‘sysadmin’;