Can't see friends server or he can't see mine?

[J3ST3R]

A friend and I have recently been having problems seeing each others servers in multiplayer. Never used to have a problem with this. We can both join other public servers but just can't see each others.

 

Public server is checked.

With or without a password makes no difference.

Tried connecting through iP and port but no joy, just get a connection interrupted message.

 

I always turn off my anti virus etc before I go online in game.

 

Any help would be greatly appreciated