Sign into Office portal with your admin work/school account.
Click the Admin tile>Users>Active users.
Check if that user account is in the list.
In the Office 365 admin center click Admin (Admin centers)>SharePoint.
Click user profiles>Manage user profiles>enter the problematic user account>Find.
Check if its user profile can be found.
Access http://YourSharePointSite/_layouts/15/people.aspx?MembershipGroupId=0, and check whether username of the problematic accounts are listed there. if not please add the user and try again .
One more possible reason may be that the user is logged in with an account that doesnt have permission, even if the error shows his work email.
https://support.office.com/en-us/article/Sign-in-to-Office-or-Office-365-b9582171-fd1f-4284-9846-bdd72bb28426?ui=en-US&rs=en-US&ad=US .
If all above still failed , you may using correlation ID and contact Microsoft support .