The error on dovecot service "Fatal: Multiple files for module var_expand_crypt" indicates that the Dovecot mail server configuration has ran into a problem where the var_expand_crypt plugin is loaded or referenced multiple times, which is not allowed for the service.

During startup, Dovecot loads its modules from: /usr/lib64/dovecot/

If more than one module exists for the same feature, Dovecot cannot determine which one to load and stops the login services with a fatal error.

Potential Causes

Common reasons this issue occurs:

1. Multiple Dovecot versions installed

Two different package versions for the service may exist on the server.

rpm -qa | grep dovecot

Example Output:

$ rpm -qa | grep dovecot

cpanel-dovecot-2.3.21.1
cpanel-dovecot-2.4.2

1. Partial package upgrade

A package upgrade may install a new version without fully removing the older version.

1. Leftover module files

Old modules may remain inside /usr/lib64/dovecot/ after an upgrade.

Steps to Resolve

Step 1: Check installed Dovecot packages

rpm -qa | grep dovecot

If multiple versions are installed, remove the older one.

Step 2: Remove the older Dovecot package

dnf remove cpanel-dovecot-2.3.21.1-2.cp108~el9.x86_64

This removes the outdated package and prevents duplicate modules from loading while the service is running.

Step 3: Verify remaining packages

rpm -qa | grep dovecot

Expected output:

$ rpm -qa | grep dovecot

cpanel-dovecot-2.4.2
cpanel-dovecot-pigeonhole-2.4.2

Only one version files should remain.

Step 4: Restart Dovecot

systemctl restart dovecot

Or on cPanel servers:

/scripts/restartsrv_dovecot

Check the service status:

systemctl status dovecot

Verify listening ports:

ss -ltnp | egrep ':(110|143|993|995)\s'

Summary

Issue:

Fatal: Multiple files for module var_expand_crypt

Cause:

Multiple Dovecot versions installed, causing duplicate module files.

Fix:

Remove the older package and restart the Dovecot service.