"SharePoint 2013 workflow HTTP Unauthorized" error occurs
When you try to run a Microsoft SharePoint 2013 workflow in Microsoft SharePoint Online, you receive an error message that resembles the following:
Retrying last request. Next attempt scheduled after Date/Time. Details of last request: HTTP Unauthorized to SharePointSiteCollectionURL ...Correlation Id: CorrelationId Instance Id: InstanceId.
Currently, the SharePoint 2013 Workflow Service does not provide Trusted Network policy support, such as for IP address restrictions. When the Workflow 2013 makes a call to the Azure Workflow Service, the response is returned to SharePoint Online from a different IP address. This behavior triggers an access request restriction and causes the "unauthorized" error message that is mentioned in the "Symptoms" section.
To resolve this issue, follow these steps:
Go to your tenant administration:
Locate Access Control.
Under the Control access based on network location setting, clear the Only allow access from specific IP address locations check box.
Currently, there are no persistent lists of the Office 365 Azure Workflow Service endpoints to add to the Allow list.
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