admin.microsoft.com inaccessible via MCAS

[ProgentCT]

With a conditional access policy applied admins are unable to reach admin.microsoft.com.  It is redirected to https://admin.microsoft.com.mcas.ms and yields a blank white screen.

There is only 1 conditional access policy.

It's settings are:

All users (with 4 admins excluded).

All Cloud Apps.

3 Conditions selected

• Device Platforms
  • Include Any Device, Exclude macOS and Linux
• Locations
  • Any location
• Access Controls
  • Grant Access, Require MFA
  • Require one of the selected controls
• Session
  • Sign-in Frequency 7 days
  • Use Conditional Access App Control (Monitor Only).  I have tried to REMOVE this setting but it comes back all by itself.

[#2]

@ProgentCT 

Error:

[#3]

You should probably contact MS support

[#4]

I did. I opened a case on 2/23 and received a call on 3/4 when I was OOF. I should be speaking with them today.

[#5]

This was a problem with MCAS and fixed by MS on the backend. There was nothing wrong with my config. I'm revisiting this today because now I have the same issue with Sharepoint. Today no user can access Sharepoint. There have been no changes in conditional access policies, it just stopped working out of the blue.