My name is Jan Vidar Elven. I’m a Microsoft MVP Enterprise Mobility and Cloud & Datacenter Architect working for Skill AS (www.skill.no) in Norway. I’m also a Partner Technology Solution Professional (P-TSP) for Cloud OS and Datacenter Management for Microsoft Norway.
I have been working in the IT industry for over 20 years, teaching and consulting mainly in Microsoft Servers and Technologies, Cloud Services and holding certifications as MCT and MCSE.
My main focus areas are Enterprise Mobility + Security and Identity and Access Management with Azure AD. I also work a lot with Cloud and Datacenter Management, primarily with Operations Management Suite, Service Manager, Orchestrator, Operations Manager and Automation, in both Azure and Hybrid Cloud environments.
GoToGuy Blog 
Hi Jan,
Thanks for your detailed azure-ad-application-proxy post.
My name is Yael and I’m facing exactly same problem with guest users trying to authenticate web app on IIS with app proxy connector.
We have Azure AD domain services (and not on-premises AD and Azure AD Connect) .
I tried to set user principal name as explained in the post, but I get:
Set-ADUser : Insufficient access rights to perform the operation
although I’m global admin and owner of the azure account.
Have you encountered such a situation?
I will appreciate any help 🙂
Best Regards,
Yael