Here is a link to a help article.
This article is for a different issue but it demonstrates this procedure
Near the bottom of the article is the section on x-box.
You will have one of the two types, probably “companion”
The article talks about uninstalling etc, you just want to sign out.
When you start the sim it should prompt you to sign back in.
It may not fix the issue, but it is one cause that needs to be eliminated