Dear Shivangi,
Greetings
Were you able to reproduce the issue ?
Can you provide more details like what more roles they have and is it conflicting with other roles ?
For example,
Our admin team members are having multiple roles to access public website and admin website.
Once they login with their public website credentials with different roles & without logging out, they try to access admin website, its giving them same permission error.
So they have to logout and login again (In your case you are clearing cache) and its working fine.
So I would suggest you to check in the direction if any role is conflicting with their active role ?
1) Try to assign only one role i.e. UserManager and try. (instead of multiple roles if any)
2) You can check what other role that person is having while they are getting permission error.
Let us know if you find something like this.
Regards,
Palak Patel