Updating steam cannot contact the steam network
In my case I just took a look at the windows update history (win7) and found out that the wlan driver was updated on march 5th.
So I rolled back that update and everything worked again.
It seems in most of the cases, Steam's problem stems from a bad Wi-fi or network driver.
It also doesn't hurt to check your antivirus or any firewalls running.
When you’re ready to go offline, click the Steam menu and select Go Offline.
Click the Restart in Offline Mode button and Steam will restart in offline mode – features like Steam’s server browser, friends, and achievements aren’t available offline.
If you don’t, Steam is supposed to prompt you for offline mode – but this doesn’t always work properly.
If Steam’s offline mode isn’t working at all, you may still be in luck – some Steam games don’t use Steam’s DRM at all and can be launched manually.
The idea of digital content soon became so popular that Steam became the go-to store for gamers around the world.Next, go to your Library tab and ensure that each game you want to play offline is fully downloaded.If you see any sort of progress indicator next to a game’s name, you can’t play it offline – ensure each game you want to play is fully downloaded and updated before going offline.To force Steam into offline mode, you can disable your network connection.If your laptop has a hardware switch for Wi-Fi, disable it.