Can't send approval flow to users outside organization
I have created an approval flow that passes a parameter in PowerApps to choose who the approver is. When I send the approval to anyone outside my organization, I receive an error. When I send the approval to a user inside my company organization, the flow runs fine. I have attached a photo of the error message I receive, as well as a photo of the flow.
The StartAnApproval_AssignTo parameter is the part that is causing the flow to fail.