Cpanel Mailman mailing lists: cannot manage lists after migrating to new host

We recently migrated 2 Cpanel servers to VPS. Most things migrated properly and without incident. However, Mailman mailing lists were the exception.

Mailing lists appear to have migrated properly, as they show up under WHM and Cpanel and usr/local/cpanel/3rdparty/mailman/bin/list_lists

However, when cpanel user clicks Manage link, the following message appears:

cpanel1.hosting.com mailing lists – Admin Links
No such list listname_domainname.com
There currently are no publicly-advertised Mailman mailing lists on cpanel1.hosting.com.To visit the administrators configuration page for an unadvertised list, open a URL similar to this one, but with a ‘/’ and the right list name appended. If you have the proper authority, you can also create a new mailing list.

This turned out to be a permissions issue:

root@cpanel1 [/usr/local/cpanel/3rdparty/mailman/bin]# ./check_perms

--snip--
directory permissions must be 02775: /usr/local/cpanel/3rdparty/mailman/.../list_domain.com/...
--snip--
Problems found: 2999

# ./check_perms -f

FIXED!!!