Cannot upload map file: Failed to parse a map file

I cannot upload my custom‑made map to the COI Community Hub.
Every time I select the  .map  file, the website returns the error: Failed to parse a map file.

The map loads normally inside the in‑game map editor, no editor‑side errors appear.
I have tried saving a brand‑new copy of the map inside the editor, and used the newly‑saved  .map  file for upload, but the parsing error still persists.
File size is well under the 50 MB upload limit.

I need help figuring out what causes this parse failure.

It might be useful to the devs for you to attach the affected map file to the report? I'm also reasonably sure that, as a Hub bug, someone will move this post to the proper subgroup of the Bugs forum.

I get this Bug too.

But if I try to Upload the one what already is uploaded, then it works normaly.

no use I did