Dec 2023
I was not receiving any notifications from airbnb on my phone and saw a lot of people had the same problem. It appears that the Airbnb App was to blame.
To fix it, I went to the Airbnb app on my iPhone, clicked the Menu button in the bottom right, clicked Settings, then Notification Settings. Here it said All Notifications were off and asked if I wanted to switch them back on. I did so. Hopefully this has fixed it. Strangely, there is no button to switch it back on. The function simply disappeared. My guess is that there was an update and this was a makeshift solution by the developers.