I contacted support, wrote this on Discord to several people and nobody knew what to do.
So, when i try to upload my custom map, It always get rejected. Just why.
It says "invalid file extension, expected zip."
I tried uploading map alone, then in RAR, then in 7zip file. Always same message. How to hell do i upload this?
I would add files in Winrar, make the archive format zip, add the map file via the "Files" tab in Winrar when you "Add" a file, and then submit that file to upload.
Not sure if 7zip is different from .zip...
I would right click on the file > send to > compressed (zipped) folder. Then try uploading that.
I also know Mapster doesn't like some files even if they are in zipped folders, like executables, but that shouldn't be your problem.