There was a problem trying to log you in. This generally happens when Steam's servers go down (which happens more often than you think). We'd recommend trying again, and if it fails then you might have to wait an hour or two before trying again. There's some debugging information below that might be useful if you're still having problems after a few hours. Use the contact form at the bottom of this page, and include the entire error code and message.
Error code: 0x0502 — Timed out trying to connect to Steam's OpenID server for redirection.