Organizing and accessing contact information in Outlook.com
I defer to the Answer by Hendrix-V. He is much better at these kinds of problems than me.
@LB said
contact lists ... “Something went wrong
I just tested using Outlook Web with both a Personal and Work email account. All OK for me. And I am not seeing any recent reports of the problems you are hitting.
1 -- Setup to do a Add Contact to List, press F12 (Browser Dev Tools), click the Network tab, execute your add to list. Do you see any failed (500 or 503) responses?
2 -- Same in a different browser? Private/Incognito browser session?
3 -- Do you have access to an Outlook Client App? If so, same problem there?
https://apps.microsoft.com/detail/9nrx63209r7b
Android: https://play.google.com/store/apps/details?id=com.microsoft.office.outlook&hl=en
iOS: https://apps.apple.com/us/app/microsoft-outlook/id951937596
Mac: https://apps.apple.com/us/app/microsoft-outlook/id985367838