In "App Store Connect -> Users and Access" I'm trying to add an app to some user.
When I'm trying to save changes I get error:
"Your account doesn’t have permission to edit other users. Contact your team agent for more information."
The problem is that I'm the admin in App Store Connect and agent in the corresponding apple developer program account.
Ok, so in order add permissions for some app to a user I've needed to change his/her role then return previous role and after that add the app. It allowed me to save the changes.