The error HTTP 401 appears when clicking on any offering or expanding folders in USS integrated with Catalog.
This occurs only with IE.
Chrome works fine.

IE limitation with URL's using underscore in the hostname

Unified Self-Service (USS) 17.1
Service Catalog 17.1

Change the URL and remove underscore or use IP address.

Related link:

https://support.microsoft.com/es-cl/help/316112/prb-session-variables-do-not-persist-between-requests-after-you-instal