Contact form "not working"

[Popolechien]

We have users regularly complaining that our contact form does not respond. I've tested it on multiple devices and browsers and so far, so good:
[x] Chrome, Firefox & Safari MacOS
[x] DuckDuckGo Android
[x] Opera on Windows11

Weirdly enough, I had no error message when using Chrome on Android and Win11 but did not receive the corresponding emails either.

What could it be that causes this issue(s)?

[kelson42]

What does exactly "does not respond" means?

[Popolechien]

Can not input text or Send command not sending anything.

[kelson42]

OK, the two scenarios are very different and I suspect it will be extremly difficult to move his ticket forward without eiter a reproduction case or a screencast.