Work.com: Coaching - Unexpected Error When Creating a Coaching Relationship
|Knowledge Article Number||000199459|
|Description||When you create a coaching relationship, both users automatically follow the record.
Some users may experience an error that says "Unexpected Error Occurred" after you try to create a coaching relationship. This is because one of the users has hit the maximum number of records they are allowed to follow. For most orgs, this limit is 500 records.
To bypass this error either request to increase this limit, or have the user unfollow a few records to free up some space.