I have tried every possible thing to fix this.

Every server I join I get:

"Confirmation of Changes: Session Lost"

Yes. There are players in the server.
Yes, it does have the green dot, so the server (every server.) is not down.
Yes, redownloaded, and reinstalled.
Yes, Dayz and Steam are allowed through the firewall.
Yes, Tried experiment also
No, I'm not banned.

Seriously. I cannot find help anywhere. I don't know where to turn. I'm completely hopeless as nothing I try is helping.
Seriously, please someone help out. I haven't been able to even join a server in days.