Webhook "demo trigger" not being received

Hi,

I’m trying to set up webhooks to go to my Home Assistant instance. I’ve sent requests manually (over the internet, not from within my local network) and HA receives and processes them correctly. However, when clicking “send a demo trigger" in the Equiwatt app (Android v5.0.93), HA doesn’t receive anything.

Any assistance would be greatly appreciated.

Thanks!