check your arma 3 files .. verify .. steam/library/arma 3/ right click on it , select properties then tab at the top ( local files )
then click verify the integrity of the game .. that should fix, but you could have a common mod that the servers your connecting to that is corrupt .. narrow it down .. unsub from the offending mod, and resub to the mod
Asking for help this way .. will get you nowhere fast .. somethings you have to figure out on your own.. it's a free service .. why do you think you are entitled to act this way >? Have you ever donated to the launcher ? It doesn't run itself .. try more sugar and less vinegar .. check your hard drive space and try google
Now I am really confused. A3 Launcher does indeed have this door mod available if you filter the mods searching for "door" but it will not allow me see my server in the list.
I can even click the "website" link from A3 Launcher and go to the Steam community page
Server check still says it is an Unknown Mod.