Twitter support has been removed from the game with 3.7.0 patch update due to limitation to API calls. All players who were using the deprecated login method were forcibly reset to "guest" authorization (which is using Google Play / Game Center ID for identification).
If you were using Twitter account for authorisation, you can now freely pick any other authorization method.
However, we highly recommend you to bind the social network account to ensure your progress won't be lost.