A user attendee can visit the call record and can join the call on the My Schedule page online. However, the user encounters a permission error when trying to visit the same call record on CRM iPad.
Why is the user unable to view the call record in My Schedule on CRM iPad?
It is because the user attendee has no visibility to the primary account of the parent call.
The user attendee needs visibility to the primary account of the parent Engage Meeting call to view the call report and join the meeting on CRM iPad.
CRM Help Documentation: CRM Users Attending an Engage Meeting