When I'm starting the launcher it says "Multiplayer ok, Login ok" and then shows the "play offline" button.

What I expected to happen was...:
The launcher shows the "Play" button.

What I did until now, was ...
Delete the .minecraft folder, delete the launcher.exe. Redownload the new launcher and start the launcher.
At the first login, I get an error in the development console. When I'm close the launcher and start it again, I get always the "Play offline" button