Error message when I try to create a local multiplayer game

[PsyBird]

When I try to create a new local multiplayer game, an error message appears after I click "OK" on the "Configuration" menu.
The error message says:
"Mandatory WML child missing yet untested for. Please report."
I have tried several versions of the game, but every game came with the same error message.
Is there anyting I can do to fix this?
I have Windows 10.

[Lord-Knightmare]

Were you trying to load a core MP map? Or, some UMC scenario? Can you provide more information? Like add-on names, scenario names, or maps using custom terrains?

[PsyBird]

Sorry for the lack of information.

It happens when I try to use my own maps created in the map editor that comes with the game.
I used no add-ons and no custom terrains.

[gfgtdf]

which wesnoth version do you use?

[Pentarctagon]

Sorry for the lack of information.

For future reference, there is a sticky at the top of the forum regarding the information needed for bug reports.

[PsyBird]

Sorry for the lack of information.

For future reference, there is a sticky at the top of the forum regarding the information needed for bug reports.

Thank you, here is the information I can give:

Operating system: Windows 10, 64 bit
Versions of the game I have tried: 1.13.7, 1.12.6, 1.12.5
I don't have a game save, since I'm not able to start a game.

[Pentarctagon]

What version of Wesnoth were the maps created with?

[beetlenaut]

I understand why you can't post a saved game, but you could post the map file. If we could look at that, we could probably find the problem.