Why is Steam not able to connect Steam-Network?

Same problem on German Ubuntu forum

http://forum.ubuntuusers.de/topic/steam-verbindet-nicht-zum-server/

This command helped me too

steam --reset

Removing appcache helped me till a new steam version was released which seems to have it fixed.

You can remove appcache via terminal

rm -Rf ~/.steam/steam/appcache

Don't do this with sudo.

I have been able to reproduce this with perfect network connectivity when steam is closed unexpectedly. The solution in my case was to remove:

.local/share/Steam/config

This solution worked for me, and didn't force me to reinstall any game, just to login again