Steam is having trouble connecting to the Steam servers

[Pkchp Xpress]

For about a week I haven't been able to connect to Steam - I get the same message. I've tried the standard fixes (check router (I don't have one), check firewall, reinstall, etc.) My account is fine, and Steam continues to download updates. I just can't log in - has anyone had this problem? Is there something wrong with my folder permissions that's keeping it from logging in?

I recently upgraded to El Capitan, version 10.11.4
(the problem happened right before I upgraded, so I thought it might fix it to upgrade)
thanks-