Issue with AoE 2 DE Multiplayer

So I just got AoE 2 De with my Friend and we were playing it for 2 Weeks now.
Since yesterday we cant join each others lobby… For me there is a message when i want to join: The Is An Unknown Error. And for him it says that he need a mod. But non of us installed any mod or got one installed. I checked it! Then I tried to contact the support but that was like the owrst support ever. He was like a bot and asked every question over and over again… I just wanna play AoE wtf… xD Pls someone help!