Maybe they broke YOUR launcher itentionally to farm your salt!
Seriously though, wait for a minute after your name turns green. If nothing happens, open the “Server List”, see if you can start and login from there. If that doesn’t work either, run network diagnostics, open the task manager of your OS (top for Linux etc.) and check if after hitting “play” another process opens or not. If you run on very low memory or your harddrive is full this might be another source of problem.