Hey Captain,
As I said above, it is now obvious, reading everything wrote up here, that the problem is related to some router/isp. However i don’t think it means that you have a problem with your router/isp. It’s just that some router/isp looks to crash under DE. (like literally crashing, AoE2:DE Kills Network Adaptor check this thread).
I have the same issue while I tested everyting I can and I have a very stable and good wifi connexion. However, as soon I play DE, I get DC of my game and see that my connexion crashed at that exact moment.
How to fix it… that’s a good question 