How to fix Outlook notifications not working after iPhone 16 Pro upgrade?

I recently upgraded from iPhone 13 to iPhone 16 Pro and now I no longer receive my Outlook notifications on my device. My iOS is iOS 18.4 (and is current as of today). I've tried deleting and re-installing the app. I've checked my iPhone Notification settings and made sure that Allow Notifications is on; checked my Alerts; made sure the Banner Style is set to Persistent; Checked Focus Mode settings; Restarted iPhone; Checked Background App Refresh.

When I tried to Check Push Notifications - within the Outlook app --- Settings - Help - Test Push Notifications - I get the error message in the image below

I've checked with my IT department and they indicated that it's Apple related...

I have not yet tried a complete reset of my new iPhone -- was hoping there's another fix versus trying that.

(They also are not coming thru on my Apple Watch - but I think that's because they aren't coming thru on the iPhone)

[Re-Titled by Moderator]