Hello everyone, I realized that on an Android tablet, a little old nextcloud app and chrome give me error on my lets’encrypt certificate. I checked the TLS policies and left the default one. I checked the ssl certificate through online sites and they tell me it’s OK. In addition, only firefox works from the tablet without reporting any errors. From the tablet I can also connect to the community that has a lets’encrypt certificate like mine, even if my public domain name is on noip.com (only resolution of the ip without any management of dns records). Do you have anything to suggest? What can I change on the choice of TLS policies?
Anyway, I think the problem is the tablet, I tried it with other devices and it works.
You may use the old chain:
Thank you for the exhaustive information!