If it says "steam failed to connect" am i banned ?
Your not banned. Here is some info i gotten
"This issue stems from four main sources: connection issues, security software, background applications and third-party anti-cheat applications."
It probably because your hacking , If not contact them
If it is when you start Steam you're definitely not. Did you get new Anti-virus or router? Are you using a Proxy/VPN?
That's probably what's causing it.
If it is when you start the game, it makes no sense.