My "Start ans wait for approval" action is raising this error:-
BadRequest. The request failed. Error code: 'InvalidApprovalRequestor'. Error Message: 'The approval requestor must be a single, valid user account within your organization.'
Although i am using valid accounts. here is the SharePoint form which triggers the MS Flow:-

Here is the Error:-

Here is the "Start and Wait for approval":-

Any idea why i am getting this error?
Thanks