Bounced for those just coming home and trying to login as there seem to be a few familiar names in the "Who's on line" section showing as stuck at 'logging in' status.
Looking at the Activity log, there seem to be fair few people experiencing this issue, as I was last night / this morning.
The solution is to check the box entitled "save" having entered your User name and password details. You should then login successfully.
Thanks and full credit to JC Footy...