While an interesting concept, I suspect the API has now been overloaded. :-/ It's possible the backing services were not sized for public-internet level traffic as a poster mentioned above.
Is the App still functioning well?
I agree with
pythonisman. I'd definitely implement some form of a caching layer in AWS or something that minimizes traffic to the actual endpoint itself. Keep that traffic from your caching layer to this endpoint to under 1 request every 1-5 minutes or so and I'm sure you'll stay under the radar just fine. I doubt the occupancy data is being updated more frequently than that anyway....
Edited to add - Link seems to be working fine again. Interesting level of data that is being returned!