I am having an issue accepting my Careers invitation. I get the following error:
Hmm, that email already exists on another account. You will need to log out of your existing account and log back in.
I was using a Google OpenID on Stack Overflow that was different from the one I used to authorize Careers but had the same details.
(Google apps accounts migration issue; I won't go into details.)
I tried to rectify the issue by associating my Stack Overflow account with my new Google OpenID, and removing the defunct one; both my StackOverflow and Careers have matching OpenIDs.
However it didn't help and I am still getting that error.