'You are not signed in some features will not be available in unity'What ffeaturres? Btw I can't sign in because there is a message Serrvice not available please try again later.
Must have been a glitch in the matrix. I too had weird behavior and could not open Unity for three or four tries saying it was not activated on this machine..which is the only machine it has ever been on.
You will not be able to auto link a new project to a online services project without signing in. So auto integration of analytics, cloud build, unity ads and the like is out. This makes pretty much no difference whatsoever. You can always integrate the features later. Or manually.