try to login with ssh to the remote machine, it will show the fingerprints. If it is ED25519 with SHA256 then type in at the remote machine:
sh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub
Source: the
apt update
apt install prosody
set the servers ip address for chat.example.org, conference.chat.example.org and upload.chat.example.org
allow firewall for port 5222 tcp for client connections
allow firewall for port 5269 tcp for connections from other servers
allow firewall for port 5281 tcp for file uploads
allow firewall for port 80 tcp
apt install certbot
certbot certonly --standalone
register and enter chat.example.org conference.chat.example.org upload.chat.example.org
nano /etc/prosody/prosody.cfg.lua
nano /etc/letsencrypt/renewal-hooks/deploy/prosody.sh
fill in
#!/bin/sh
/usr/bin/prosodyctl --root cert import /etc/letsencrypt/live
my workaround to force import of certificates: certbot renew --force-renew --deploy-hook "prosodyctl --root cert import /etc/letsencrypt/live"
uncomment VirtualHost "localhost"
add VirtualHost "chat.example.org"
save and exit Ctrl+X y ENTER
systemctl reload prosody
...
apt install coturn
https://prosody.im/doc/coturn