ERR_CONNECTION_TIMED_OUT on 4G connection only

On youngcompetitions[dot]com the website works fine mostly. However, on some 4G connections on mobile devices we get a timeout ‘ERR_CONNECTION_TIMED_OUT’
Not every device is experiencing this.
We also notice that the NS is not propagated everywhere? We get some errors.

I have been looking at that domain, and it looks from my end, to be working perfectly fine, including on various testers that test from multiple locations worldwide.

It is however doing a redirect to a .CO.UK domain.

Can you elaborate on where you see these issues?

  1. What ISP / provider, preferably their AS number?
    The provider’s AS number can be found by visiting various sites through the 4G, e.g.:
    https://bgp.he.net
    https://bgp.tools

  2. What country (and eventual state/region)?

Where and how exactly are you looking at the propagation?

And what kind of errors do you see there?