(Syncing Map Failed) Error trying to play my own custom map via multiplayer

[FlashTech]

My custom maps seem to work fine in Skirmish mode. My friends and I are able to Subscribe to my custom map but everyone gets the "Syncing Map Failed" error when trying to load the map in multiplayer, so we cannot play together.

Here is a screenshot of the error:
https://photos.app.goo.gl/xnFKCtzRddJXrZy3A

Here is a screenshot of it working in Skirmish:
https://photos.app.goo.gl/HibEieWLSWCekR7V7

Here is my map in the workshop:
https://steamcommunity.com/sharedfiles/filedetails/?id=3419298856

Here is a direct link to my map file:
https://drive.google.com/file/d/1BrW4ZUW2AX45iehEFle2G1wkFXDDeLwX/view?usp=sharing

I'd like to make more maps and get more friends into 8-bit armies/hordes/invaders.
I'll take any suggestions. I've looked around the internet for any ideas but couldn't get past this issue.