When outbound email stops working on a cPanel server, one of the most common Exim errors is:

retry time not reached for any host after a long failure period

This message appears when Exim repeatedly attempts delivery to a remote host but temporarily gives up because all retry intervals have not yet expired. As a result, emails sit in the queue and never leave the server.

This issue is extremely common on cPanel servers using Exim, especially after migrations, DNS changes, IP reputation issues, or mail delivery failures.

If you want experts to fix your mail delivery and clean your queue safely, check our Email Deliverability Specialist or cPanel Server Management services.

1. Why Exim Shows “Retry Time Not Reached”

Here are the actual root causes (not generic copy-paste answers):

1. DNS resolution failures

If your server cannot resolve MX/A records of the recipient domain, Exim delays delivery.

Common reasons:

  • Wrong resolvers in /etc/resolv.conf

  • Firewall blocking DNS

  • Broken / slow upstream DNS

  • DNSSEC validation issues

2. Remote host unreachable

If the recipient mail server times out or rejects connections, Exim increases retry intervals.

Example logs:

Connection timed out
Remote host closed connection
Refused due to policy

3. Exim retry database corruption

The retry DB (/var/spool/exim/db/retry) can become corrupted after:

  • Forced reboots

  • Disk full events

  • Interrupted Exim restarts

4. IP reputation / blacklisting

If your server IP is blacklisted, remote servers delay or throttle acceptance.

5. Mail queue overload

Large queues (>5,000 messages) slow down retries and increase retry delays.

6. Incorrect routing after cPanel migration

Old routing data stuck inside Exim can trigger long retry cycles.

2. How to Fix “Retry Time Not Reached” (Safe Production Steps)

Follow these steps in order. Each step is safe for live servers.

Step 1 — Check Exim main log

tail -f /var/log/exim_mainlog

Look for:

  • “connection timed out”

  • “refused”

  • “retry”

  • “no mail servers for domain”

Step 2 — Test DNS resolution

dig mx iserversupport.com
dig iserversupport.com

If DNS is slow or failing:

  • Update resolvers in /etc/resolv.conf

  • Use 1.1.1.1 or 8.8.8.8

Step 3 — Test SMTP connectivity

telnet mail.iserversupport.com 25

Check for:

  • Timeout

  • Connection refused

  • Banner issues

Step 4 — Clear the retry database (MOST IMPORTANT FIX)

If retry DB is corrupted:

rm -f /var/spool/exim/db/retry
rm -f /var/spool/exim/db/wait-remote_smtp
systemctl restart exim

This forces Exim to rebuild retry data fresh.

Step 5 — Force delivery of all messages

exim -qff

Or for a single message:

exim -v -M messageID

Example:

exim -v -M 1qx1bc-0002aa-9J

Step 6 — Check mail queue size

exim -bpc

If huge:

exim -bp | exiqgrep -o 86400 -i | xargs exim -Mrm

This removes messages older than 24 hours.

Step 7 — Restart Exim cleanly

systemctl restart exim

On older systems:

service exim restart

3. Additional Fixes If Mail Still Doesn’t Deliver

Fix SPF, DKIM, DMARC

Broken DNS records cause major deferrals.

Run:

dig txt iserversupport.com

Or use your own checker:

https://mailtested.com (highly recommended)

Fix hostname and reverse DNS

Ensure:

  • Hostname resolves

  • PTR record matches hostname

  • No mismatches in mail_HELO_name

Remove broken Exim configs

On cPanel:

WHM → Exim Configuration Manager → Reset to Default

4. How to Prevent This Error

  • Use stable resolvers (1.1.1.1 or 8.8.8.8)

  • Monitor queue size

  • Enable CSF rate-limit alerts

  • Avoid brute-force firewalls blocking outbound connections

  • Keep Exim updated via cPanel

  • Monitor IP reputation

  • Fix invalid SPF/DKIM on hosted domains

For hands-off management, our Linux Server Management service handles this automatically.

Conclusion

The “retry time not reached for any host after a long failure period” error means Exim has postponed delivery due to DNS failures, remote host issues, corrupted retry databases, or routing problems.

With the steps above, you can safely rebuild the retry DB, restart Exim, fix DNS, and restore normal mail delivery.

If your queue is stuck, messages aren’t delivering, or you need professional investigation, our team can help under Email Deliverability Specialist or cPanel Server Management