I prefer playing custom maps. I downloaded this.
1035 KW maps. Playing on 3840x2160 made scrolling through the map list impossible, it skipped ahead and I couldn't see all the maps. Playing at 5760 x 3240 was better as I could scroll through the map list and sort them normally but the issue was it was showing some of the 8 player maps labelling them 6 player, I don't know if that contributed to the problem online but I doubt it.
The main problem was when I hosted a game, I saw on c&c online, the name of the map I was hosting was appearing different so everyone who joined the game was seeing a different map name (a different map name that is actually a real map) than what I was seeing. So I started a game when a person join and he instantly got disconnected when the game started, I tried again with someone else and the same thing happened. What is going on here? Why are people seeing different map names than what I see? I am pretty sure I installed the maps correctly, I just dragged them from the winrar zip right into my map folder.