ArcGIS Workflow Manager server is not licensed. Please contact your Administrator

Error Message

When logging in to ArcGIS Workflow Manager in ArcGIS Online, the following error is returned:

Error:   
ArcGIS Workflow Manager server is not licensed. Please contact your Administrator.

Cause

The incorrect license is assigned to the user in ArcGIS Online. When assigning the license to the user, the add-on license of the ArcGIS Pro extension is selected instead of the user type extension for the ArcGIS Workflow Manager license in ArcGIS Online. This occurs when selecting the 'Add-on licenses' tab on the Organization page.

Solution or Workaround

In ArcGIS Online, assign the user with the Workflow Manager user type extension license. Refer to ArcGIS Online: Configure user type extensions for further instructions. Ensure the ArcGIS Workflow Manager license selected is in the 'User type extensions' section instead of the 'ArcGIS Pro extensions' section as shown in the image below.