hehe, so … if you ever change the hostname of a Linux machine, you really really ought to double-check /etc/hosts to make the same hostname change there
it’s surprising just how much will break if a machine’s own hostname isn’t resolvable to a 127.x.x.x address :P
If you have myhostname set for hosts in /etc/nsswitch.conf it shall take care of this for you (should be the default on most systemd distros I believe? not sure)