"This operation can not be completed at this time" during add MS Intune subcription to CM

You are attempting to add a Microsoft Intune subscription to your ConfigMgr site and the "This operation can not be completed at this time" message appears.  Fun.  Maybe if you try it later it will work?  Probably not.

This typically means that the Intune tenant you are attempting to associate with CM (and thereby set CM as the mobile device management authority) already has the authority set to something else (typically Intune). This may happen if you were using Intune as a standalone implementation for a bit and then decided to integrate it with CM.  In order to address this, run, don't walk, to your computer and open a Microsoft Premier support incident to reset the authority.  Although Microsoft says the authority cannot be changed it may be possible but you'll need to engage a Premier support engineer to do it.  The reason you should run is the turnaround time can be 24 hours or more (maybe even 5 days) for this change to take affect.  Once you open the support incident you can save some time and be proactive on the steps that the engineer will ask you to perform before the authority reset is started.

Open the Intune portal (manage.microsoft.com) and:

• Retire any enrolled devices.  Selective wipe is OK.
• Delete any sideloading keys
• Delete any certificates (like iOS APN) that were added to Intune
• Delete any apps that were added to Intune
• Delete any policies that created