Calendar has never worked for me... If I add a meeting on the phone after just a few min it will disappear. It'll still show up on my win10 laptop or if I login to Hotmail but never on my phone... Any know fixes?
Unfortunately still nothing
Ok, I tried something a bit extreme. I did a hard reset and did not restore from a backup. The calendar now works perfectly. Even though this is very inconvenient, it does resolve the issue. I suspect that when I initially brought up the phone out of the box, having the phone use the backup from my Lumia 1520 did something that really confused the phone. I'm going to spend the rest of the day manually configuring the 950XL to the way my Lumia 1520 was.