Game over? [86420]

Hi,
when I´m trying to play mkw online, I receive error code 86420.
(I can sometimes find players.)
Can someone help me?
I have done all of these things listed below:

• Manually assigned ip-address and DMZ
  
• Primary and secondary DNS (8.8.8.8 and 8.8.4.4)
  
• Port forwarding (UDP 1024-65535, TCP 29900-29901)
  
• Firewall is off
  

And yes, I use 4G connection, is that my problem?