I get this when I try to re-enter a timed out WebDirect session:
502 - Web server received an invalid response while acting as a gateway or proxy server.
It doesn't give me grief with normal credentials, only when I use Google oAuth AND multiple web publishing servers. So, it redirects me, but then won't let me back in. Likely an issue with the Google API settings (which I have played with), but still - I can't seem to get oAuth to like the extra server unless it is directed their INITIALLY from the primary link. Revisiting the primary link is obviously a pain and non-intuitive, so looking for another set of thoughts as mine are not leading me to the solution...