Have you updated your server to the newest dedicated server?
2018-11-15 is the newest version.
https://forum.maniaplanet.com/viewtopic.php?p=302718#p302718
Newly created maps in ManiaPlanet 4.1 can't be loaded onto old servers, and when they are, the server simply skips them. I'm guessing this is probably what is happening to your maps.