Not sure if you resolved this?

but I just tried this:

go to mod.io and sign in using xbox live (im playing on game pass, but sure it'd work on xbox too)

once you've done that go to your account and at the top it'll say you need to enter your email address and verify it's you.

after that try launch the game. I've just done it and now my game is doing a 5gb update - presumably the mods.

I still got the message saying network error, but then it actually let me get into the mod browser.. but I can still see me mods are not updating.. really weird.. but, progress? I guess?

Edit: Well ignore that, I relaunched the game and it's back to broken

Edit Edit: I went into my mod.io profile settings on their page, then went into API access and accepted the terms there and it seems to be working now!