Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
It produced this output: Kein Verbindungsversuch unternommen: Mögliches Sicherheitsproblem. Firefox hat ein mögliches Sicherheitsrisiko erkannt und daher stroemi.dyndns.org nicht aufgerufen, denn die Website benötigt eine verschlüsselte Verbindung.
My web server is (include version): NextCloudPi 26.0.3
The operating system my web server runs on is (include version):Raspbian
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don't know):I don't know
I'm using a control panel to manage my site (no, or provide the name and version of the control panel):
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):
For explanation: On 16th of January 2025 the certifucate was etsimated as not valid, although the certificate showed end date of 16.01.2038. The NextcloudPI letsencrypt-menu showed a valid certificate. Something must be wrong with that.
goestr
The error message in German, as far as I can tell with my limited German knowledge, does not specifically point to the certificate.
Also, from my point of view, stroemi.dyndns.org is down entirely and Let's Debug seems to corroborate this. Thus it's not possible to debug your site.
Note that multiple certificates were issued recently: https://crt.sh/?q=stroemi.dyndns.org&deduplicate=Y. Please realise that "Something must be wrong with [the certificate]." is highly (up to almost certainty) unlikely and that re-issuing perfectly good certificates is not necessary. Notably I don't see any "must staple" extension, which IMO could be the only certificate-related thing that could result in TLS connection problems.
I must apologize for multiple certificates. The issue was solved. The reason for this issue was an update to Fritz!Box 8.02. In this update IPv6 was unvoluntarily marked. Two hours after taking off this mark everything was OK.
Thank you for support!
goestr