Whenever I try to access the Steam community market, it just shows "Error -310 (unknown)". Googling got me nowhere. Has anyone heard of this error/know how to fix it?
Steam's errors usually correspond to HTTP status codes. While there are some that may indicate a problem on your end (like a connection failure or expired authentication) this one is a bit special (it's not usually listed with the "standard" HTTP codes) and means "too many redirects". It hints at a server-side problem, for example a programming mistake.