Might be because of that server jump a few days ago, I experienced something similar when that happened. I wasn't able to connect to a map, the server went offline and came back later and I everyone was able to connect.
If you still have the map in Map Maker, you can re-export it and it might work. Replace all the old files in your exports folder with the new ones. If it works then you can re-upload it and give the link to your friends.