My Lands: Black Gem Hunting

I was on here a few months ago, village doing well and doing good. But one day I could not log on, it said I was not registered as a player. Why? Tried for a few days and just gave up, now it seems through an e-mail it has let me back on, why?

There could be several reasons for that (getting "not registered" error):
- wrong login information,
- wrong caching (clearing cache and cookies helps here).