When a user attempts to add a default Account Team to an Account they own, the operation fails with one of the following errors:
Lightning Experience error: "Default team failed. We couldn't add the record owner's default Account Team. Try again, or contact Salesforce for help."
Salesforce Classic error: "Insufficient Privileges: You do not have the level of access necessary to perform the operation you requested. Please contact the owner of the record or your administrator if access is necessary."
This error occurs when the user's Role has the Opportunity Access setting configured as: "Users in this role cannot access contacts/opportunities/cases that they do not own that are associated with accounts that they do own." This restriction prevents the default Account Team from being added successfully.
To resolve this issue, update the Opportunity Access setting on the affected user's Role to allow editing of all opportunities associated with accounts they own.
After saving, the user can successfully add the default Account Team to accounts they own.
See also
Guidelines for Setting Up Default Account Teams
Considerations for Account Access via Teams
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