Steam crashing and won't download game
Solution 1:
You didn't mention if you tried restarting your router. Try that.
Really you should be able to diagnose this yourself by Googling the error.
If restarting the router doesn't work, try the following:
Open your terminal (normally done my entering "cmd" after pressing Windows Key + R) and enter:
netsh winsock reset
Source:
https://steamcommunity.com/discussions/forum/1/1457328846184701699/