Login failed for user ‘Kenneth_Test’. (Microsoft SQL Server, Error: 18456)
How do I fix it
Simple enough. Change the password. However, there are a few warnings here. If you change the password and it’s being used by someone (for example this is an application id) you may be breaking the application. If this is production, that could be a no-no. Just in case I like to back up the password hash before changing it.
I’ve also gone back to the well several times over the years with this blog post showing what the various error states mean when you get error 18456.