GMX/WEB.de: Unknown certificate found / How to check authenticity?

[xperia-xz1]

Hello,

I experience the same issue. I guess, the issue is the base URL https://kalender-bs-ddos.gmx.net/ of my calendar, which is not part of the certificate delivered. Only https://kalender.gmx.net/ and some other sub domains of gmx.net are part of this certificate.

I added my calendar providing email address. I will try to figure out, if I can re-add the calendar providing URL and email address.

[rfc2822]

I could reproduce the problem (add a GMX account).

[rfc2822]

The reason is: DAVx⁵ looks up the SRV records of GMX which are:

$ host -t SRV _caldavs._tcp.gmx.net
_caldavs._tcp.gmx.net has SRV record 0 1 443 kalender-bs-ddos.gmx.net.

So, GMX servers says the CalDAV service is at https://kalender-bs-ddos.gmx.net:443. When you access this URL, the certificate is invalid. You can easily check this by opening the URL in a browser.

Could you contact GMX that their SRV records are wrong, providing this thread as reference?

[rfc2822]

Same for web.de:

$ host -t SRV _caldavs._tcp.web.de
_caldavs._tcp.web.de has SRV record 1 1 443 kalender-bs.web.de.

$curl https://kalender-bs.web.de
curl: (51) SSL: no alternative certificate subject name matches target host name 'kalender-bs.web.de'

[papierkorb]

Für die genannten Domains wurden gestern wieder funktionierende Zertifikate hinterlegt. Bitte verifizieren, ob das Problem damit gelöst ist.

Eventuell kann es vorkommen, dass ältere Android Versionen (<4.3) trotzdem nicht damit zurecht kommen, da die ausstellende CA nicht im Zertifikatsstore des Betriebssystems enthalten ist/sein könnte.

[rfc2822]

@papierkorb Thanks, works here again!

@Oystercatcher @xperia-xz1 Can you confirm that it’s now working again for you, too?

[papierkorb]

@rfc2822 Sorry, I didn’t thought about answering in English. At least good, that it works again.

[xperia-xz1]

Works for me.

@papierkorb Thanks for fixing this so quickly!

[papierkorb]

@xperia-xz1 Sorry for the inconvenience. This shouldn’t have happened in the first place.

[Oystercatcher]

Sorry for the delay: Works for me!
Thanks a lot for helping!