people keep complaining on my server, that every time they log off and log back on their pins disappear.

can you try and see if it happens on a server with just the mod on?

I cant replicate. I tested on fabric version on a server.
Can you verify the mod is saving stuf in the map_atlases folder?
look in your instance directory /map_atlases/multiplayer folder. there should be some files named with the ip of the server

Hi. I'm having this problem on my server and checked and it is not adding any files to the multiplayer folder. What can I do to fix this? I appreciate the help!