Beachsled has it right.
It even states somewhere that the number may change.
Use your InReach address.
The number does change but my understanding is if you reply to that number it should work but it doesn't, i will try the address in my profile tomorrow when i get home.
It's also important to continuously do the updates. I once got the message a day later. I was a few updates behind.
i would 2nd thisYou tried contacting Garmin?