Running EnhanceCP/Postfix on Ubuntu 24.04. Today emails got stuck in the queue with no changes made to the server. Sharing the details below, looking for advice.
postqueue -p output
XXXXXXXXXXXXX 12433 Fri Apr 10 10:42:20 info@domain1.gr
(delivery temporarily suspended: Host or domain name not found. Name service error for name=recipient-domain1.gr type=MX: Host not found, try again)
recipient@recipient-domain1.gr
XXXXXXXXXXXXX 154540 Fri Apr 10 12:01:38 info@domain2.gr
(Host or domain name not found. Name service error for name=recipient-domain2.gr type=MX: Host not found, try again)
recipient@recipient-domain2.gr
-- 3388 Kbytes in 78 Requests.
DNS works fine from the shell
dig MX recipient-domain1.gr
; ANSWER SECTION:
recipient-domain1.gr. 86400 IN MX 10 mail.recipient-domain1.gr.
systemd-resolved is running
● systemd-resolved.service
Active: active (running) since this morning
Status: "Processing requests..."
postconf output
smtp_dns_support_level =
lmtp_host_lookup = dns
What didn't work
Graceful Postfix restart
Mail service restart from EnhanceCP panel
Eventually resolved with a full server reboot, but I'd like to understand the root cause and have a proper fix for next time.
Any ideas?
