I have some IoT devices connecting to an nginx server periodically, using ssl.
The server is configured with a letsencrypt certificate and configured with:
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
This was running for years without a problem.
However my devices can't connect anymore since the server got the newes letsencrypt certificate today: 2021-06-01
If I change to an older certificate, it works again (OK i get a warning the certificate is not valid but the communication is working)
Any help ?