The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
@Torium1
C:\Users\havie\OneDrive\Документы\My Games\
Supreme Commander does not like OneDrive and has problems with cyrillic names.
Please first try to disable OneDrive and try again.
@Exselsior
He posted the game log, there you can see what mods he is using:
debug: Active mods in sim: \000{ }
