I had this problem too. Command "systemctl status pveproxy.service" returned "start failed - failed to get address info for: myoldhostname: Name or service not known" so i did "hostname mynewhostname" (mynewhostname do not contain any dots, should be only first part of the fqdn!), /etc/hostname and /etc/hosts should contain proper hostname and IP. Then i reload networking, restarted pveproxy "service pveproxy restart" the "worker" started. It may show this "/etc/pve/local/pve-ssl.key: failed to load local private key (key_file or key) at /usr/share/perl5/PVE/APIServer/AnyEvent.pm line 1626." One may try command "pvecm updatecerts", restart or reboot. It started working for me then.