can't log into

I can log on fine to just fine. In fact it remembers me when I come back. However will not accept the same username/password combination. Also I get logged into this forum just fine.

Any ideas?

According to your normal OSM username and password is required, what seems to be correct if you can log in and log out at main site and forums here.

Have you tried to use another browser? Maybe delete all or some cookies in internet browser? Capital letter instead of small letter?