Could not open archive dir for / Could not open archive mbox dir

/usr/local/cpanel/scripts/update_mailman_cache

How to fix the errors

Could not open archive mbox dir for somelist: No such file or directory at /usr/local/cpanel/Cpanel/Mailman/DiskUsage.pm
Could not open archive dir for somelist: No such file or directory at /usr/local/cpanel/Cpanel/Mailman/DiskUsage.pm

Solution

If we have a list named list1_webinformat.com the error is

Could not open archive mbox dir for list1_webinformat.com: No such file or directory at /usr/local/cpanel/Cpanel/Mailman/DiskUsage.pm

and we have to create 2 dirs

mkdir /usr/local/cpanel/3rdparty/mailman/archives/private/list1_webinformat.com.mbox

mkdir /usr/local/cpanel/3rdparty/mailman/archives/private/list1_webinformat.com

After we create the needed directories we run 2 commands

/usr/local/cpanel/scripts/fixmailman

/scripts/update_mailman_cache

Let me know in comments if you need any help or if this helped you.
Happy coding 😉