I have a Mavic 3 Pro with an RC controller. For months I have been creating flight missions on Waypointmap.com and uploading them into the controller via an SD card.
Recently my controller has stopped recognising them so I no longer have that option.
What has changed?
There have been no firmware updates for the RM330 controller since July, so I’d guess nothing has changed there (unless you’ve not tried since July).
Did waypointmap change something at their end maybe? 
In what way? Could you be more specific please David @Keltoi? What exactly happens when you try?
So, you insert the SD card. Swipe down on the controller. Explore SD card. Copy the kmz. file into waypoints in controller. Rename the kmz file to an existing files name, then delete the original file.
That should put it into your waypoints. But it doesn’t do that anymore
No, Waypointmap hasn’t changed. I can still upload them to my RC2 controller for my Mini 4 Pro.