SummaryWhen running a workflow with a Send an Email action, the workflow might fail with the following error: An unhandled exception occurred during the execution of the workflow instance. Exception details: System.ApplicationException: HTTP 400
- Delete the current Send an Email action from the workflow and create a new one.
- Open action to configure it.
- Select the 'External Recipients' check box.
- Input desired email addresses.
- Save workflow and publish.