We're looking into this now. Were you using 3.0.2 before, or something earlier than that. I can confidently say that the 3.0.2->3.0.3 upgrade should not have had any affect on this due to the extremely minor change in that release. If it was 3.0.1 or earlier, that will help say "maybe it is JFBConnect".
Either way, there's another post of another user who can't log into the admin area (too many redirects), which is essentially the same as your error... each login failure would be a redirect, but yours isn't failing. Not sure where this is coming from, but if you have any information about how your admin area login page may be different, that could help. Things like a plugin that logs users into the admin area automatically if they're already logged into the front-end, or things like that.
Going to go poke around now, but we can easily miss some 'different' configuration settings that we're not used to seeing... so any information you can provide can really help.
Thanks!
Administrator Login Not Working
