Been having the same issue with my server not showing up aswell. This never used to happen the past several times I used the service for this game.
Update: it may have been coincidence but I decided to give it a try after seeing a error steam api64.dll could not load/missing and doing some searches online I was told to try disabling EAC on your server. FOR NOW it works fine now so give it a try until update fix is released.
