A few people have reported that uninstalling eu4 and uninstalling steam helped(but I don't think that this does anything more than the previous options).Do a clean reinstall as described in my guide on reddit about common startup problems with version 1.29.You could also delete it, but then you lose all save games and screenshots which are stored there. move the folder "Paradox Interactive\Europa Universalis IV" from your Documents folder to some other place.One player's computer acts as the 'host.' Other players are 'clients.' Thus, if the 'host' quits the game, crashes or becomes disconnected from the Internet, the entire game would be offline. Multiplayer games have a different start screen than single player games.
If this fixes your problem, you can activate achievement-compatible-mods again one by one to see which one is causing the issue. EU4 allows players to use a number of different multiplayer options and features. (You can move them to a completely different folder if you don't want to delete them).
#Eu4 multiplayer guide steam reddit install
Also remove custom mods that you didn't install via steam. Remove also mods which should be compatibly with achievements. remove all mods and unsubscribe from them in steam.clearing the download cache in steam and verify the integrity of game files afterwards.verify the integrity of game files in steam.delete the files events/SpreadOfCalvinism.txt and events/SpreadOfProtestantism.txt and common/units/iroquis_rifle_scout.txt(not iroquois_rifle_scout.txt) and decisions/Canals.txt from your game installation if they exist (the first two should not exist anymore in 1.30 or newer and the third one should not exist in 1.31.5 or newer and the fourth one should not exist in 1.32 or newer, but sometimes steam doesn't delete them).