There was an upgrade a while ago which changed the way logging in works. Your browser was trying to use an old style of authorisation code that no longer works - basically it was stuck with the key in the door and did not notice the new keypad it could use to get in instead 🙂
Someone suggested clearing your cookies that could be a possible fix.
Yup this worked. Strange. It kept showing me 500 errors so I thought something was wrong with the site
There was an upgrade a while ago which changed the way logging in works. Your browser was trying to use an old style of authorisation code that no longer works - basically it was stuck with the key in the door and did not notice the new keypad it could use to get in instead 🙂