Unable to create project in ArcGIS Enterprise. Create Service exception 'Unexpected: no hosting server available'

Error Message

In ArcGIS Enterprise, attempting to create a Workforce project in ArcGIS Workforce fails and returns the error message below.

Error:
Unable to create project. Create Service exception 'Unexpected: no hosting server available.'

In addition, an empty folder of the project is created on the ArcGIS Enterprise content page.

Cause

The ArcGIS Enterprise portal is not federated with an ArcGIS Server site. Thus, Portal for ArcGIS is not configured with a hosting server and a relational data store. When creating a project in ArcGIS Workforce, a folder containing web maps, hosted feature layers, and tables is created and published to Portal for ArcGIS. A hosting server must be registered in Portal for ArcGIS to allow this.

Solution or Workaround

1. Federate the ArcGIS Server site with the ArcGIS Enterprise portal. Refer to Portal for ArcGIS: Federate an ArcGIS Server site with your portal for instructions.
2. Configure a hosting server and register the hosting server in Portal for ArcGIS. Refer to Portal for ArcGIS: Configure a hosting server for instructions.

If the error persists even if a hosting server is configured, ensure the server site is running.

1. In the ArcGIS Enterprise site, navigate to Organization > Settings > Servers.
2. Click Validate server sites.

If the server site fails to validate, ensure the ArcGIS Server service is running on Windows. On the server machine, navigate to Control Panel > Administrative Tools > Services.

1. If the Portal for ArcGIS service is not running, right-click the service and click Start.
2. If the Portal for ArcGIS service is running, right-click the service and click Restart.