Apparently, Paizo's site works except the part that logs you in to their forums. You get a message as if your password and username doesn't exist. If you're not on social media I thought this would help. Basically it's not you.
There's a thread about this on their forums. Brian Bauman, Paizo's Software Architect, said the following:
We had an outage today with the servers keeping track of our session information, which is crucial for making log-ins "stick". We finished repairing the problem around 5:00 PM PST, but sessions from before then won't work properly. Anyone having trouble signing in should be able to fix the issue by deleting their paizo.com cookies and attempting to log in again.