I just tried uploading a new app and it fails. The old location still works.
I just tried uploading a new app and it fails. The old location still works.
When it fails, exactly what do you see?
"Sorry, your message couldn’t be submitted because we’re having trouble communicating with our servers. Please try again later." In a red field.

Thanks—I'm seeing the same problem, but I wanted to make sure it was consistent with your experience. I've already got the App Store team investigating.
It is solved.
Well, not really. I mean it was. I definitely used the new URL for a few days. However today it's totally blocked. This is what I see when I'm on a page where I should be able to see an app:
https://apps-developer.garmin.com/apps/f3d3e935-bd79-4c10-8d6a-2d0dae95d512

and this is what I see on https://apps-developer.garmin.com/

(yes, that's the whole page!)
I get the same from my mobile phone, but with my laptop things work fine for now, in my experience with cloudflare issues come stay and sometimes go.