HTTP 502 error

My app’s URL:

I’m getting a 502 error when trying to access my app. I’m in New Zealand.
I’ve tried a VPN to try other locations eg USA, Hong Kong where I don’t get an error.
The error occurs in NZ and Australia. Wifi and 4g
It’s very frustrating because I’m sitting here about to present the app to my colleagues.

@Mark

It works here in Vietnam, if that helps.

It started working after a while - sadly after the presentation finished. I was going to pitch my boss to move the app to the paid version. Not much chance of that now. Glideapps.com came out looking pretty feeble, and so did I.