

It would be valid if it would be served by the XMPP server, but it is not:
% openssl s_client -connect xmpp.jp:5222 </dev/null -starttls xmpp
CONNECTED(00000003)
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = E8
verify return:1
depth=0 CN = xmpp.jp
verify error:num=10:certificate has expired
notAfter=Jun 5 10:51:05 2026 GMT
verify return:1
depth=0 CN = xmpp.jp
notAfter=Jun 5 10:51:05 2026 GMT
verify return:1
---
Certificate chain
0 s:CN = xmpp.jp
i:C = US, O = Let's Encrypt, CN = E8
a:PKEY: id-ecPublicKey, 256 (bit); sigalg: ecdsa-with-SHA384
v:NotBefore: Mar 7 10:51:06 2026 GMT; NotAfter: Jun 5 10:51:05 2026 GMT
...







I changed from Gnome to KDE to fix the framedrops in Firefox YouTube. Intel i7-13700H.