This is the first time I've reinstalled Steam, and I keep getting this error, constantly. I went to their troubleshooting page, and every single resolution they propose is client-based. It doesn't seem to even acknowledge Valve's potential culpability in the matter. So is it actually a Steam issue, or is there something f'ed with my connection? Everything else works fine, I have no firewalls, my computer is DMZ, and it worked fine before the reinstallation.