Empty response from timetables and arrivals endpoints


am trying to access timetables, platform name, inbound, outbound information. I have tried pretty much every endpoint with different naptanIds

First link suggests that I can access the inbound/outbound data but I get no resource found

https://api.tfl.gov.uk/Line/Southeastern/Timetable/910GCANONST https://api.tfl.gov.uk/Line/Southeastern/Timetable/910GCANONST/outbound

This supposedly sends arrival information on stations https://api.tfl.gov.uk/StopPoint/910GCANONST/Arrivals

I have also tried these with api keys - no difference.

Any idea what I am doing wrong?