A while ago, we discovered that when registering accounts on MMA the system sets a maximum password length at 20 characters but in no way infers this to the end user. On the forum, password input is impossible after reaching the maximum length, but can go unnoticed due to passwords being obscured during entry. It looks like you're typing further *'s but they aren't actually going in. The main site doesn't do this, it just lets you keep typing, so can lead to longer passwords being input and thus subsequently rejected as incorrect. 

For example, if you set your password as:

ThisIsAReallyLongPassword (25 characters)

It would actually only be saving:

ThisIsAReallyLongPas (20 characters)

If you've used a long password, this is probably the issue. Try logging in by reducing your password length to the first 20 characters or changing it via the forum to one of 20 characters or less.

If this still doesn't allow log-in or you've already used a password of 20 characters or less please get back to us and I'll try resetting your account manually. But we need to rule this out first.