SSL Untrusted Certificate on mobile version of https website, other versions OK?

Viruses and worms
1

I get a Google Safebrowsing warning and a SSL Untrusted warning for htxps://fotowedstrijd.eu
while I can visit that website normally on my computer (no warning)

See sitereport: http://toolbar.netcraft.com/site_report?url=https://fotowedstrijd.eu

Striking is that visiting the IP url also gives a similar invalid certification alert: -http://138.201.254.231/auth/login

What could be causing such anomalities aka hickups? Could the errors be here on this Hetzner server?
Re: https://observatory.mozilla.org/analyze.html?host=srv115.stilict.nl
See: https://www.htbridge.com/ssl/?id=40522566b62b90946b6c3c61ffe8ff17d5fd8e00cc6c98307bcd3249c0b50a23

polonus

2

Dear folks,

The issue is that the Windows server is not presenting the complete certificate chain.

Indeed encountered with Comodo and encountered on Android.
This is the cause of the problem: https://ssl.comodo.com/support/untrusted-certificate-error-on-android.php

info source: Comodo Knowledge Base SSL,

polonus (volunteer website security analyst and website error-hunter)