ArcGIS Hub item returns the Page Not Found error

Description

In ArcGIS Hub, when the URL of an item is shared directly from the ArcGIS Hub site, accessing the shared link returns the following error message, preventing access to and sharing of the content.

Error: 
Page Not Found

Cause

The item is not added to the content library of the ArcGIS Hub site or has been unshared from the content group. Items must be in the content library to be searchable on the site and accessible through ArcGIS Hub links. Refer to ArcGIS Hub: Content libraries for more information.

Solution or Workaround

Add the item to the content library in ArcGIS Hub

On the ArcGIS Hub site, add the item to the content library. Refer to ArcGIS Hub: Add existing content to add existing ArcGIS Online items or ArcGIS Hub: Add groups of content with the Groups Manager to add content from the group with which the item is shared. When an item is added to the content library, it is automatically added to the site's content group in ArcGIS Online.

Share the item with the content group in ArcGIS Online

In ArcGIS Online, share the item with the ArcGIS Hub site's content group to make the item available on the ArcGIS Hub site. Refer to ArcGIS Online: Share items with a group for instructions.