Nobodyknocks As a tester I know sometimes they code things differently for different browsers and different devices. In my experience it's best to give as much info as you can.
A SS of that crash page would be helpful. I often get a 404 error when clicking genre's when my internet speed is slow. So I know webnovel definitely has some cache or time out issues. This sounds like a separate issue affecting only the inbox, a screenshot of that crash error may be the proof needed for IT to step in and actually take this bug report seriously.
I will try too th, on my Samsung using chrome to see if I experience the same.