I am receiving reports of and am experiencing myself intermittent problems logging into the forum. From researching this issue, it appears that there are some type of access attacks being made against a variety of forum software products where the attacks pick up the names of users and then attempt to force passwords until they get in - perhaps hoping to get through to an administrator's account.
I am monitoring for a patch to the forum software to address this and will install a supported patch if and when it is released.