In future Cpanel updates, /etc/cpanel_exim_system_filter may get overwritten if you edit it.
Solution:
- cp /etc/cpanel_exim_system_filter /etc/cpanel_exim_system_filter_custom
- Then edit /etc/cpanel_exim_system_filter_custom and remove the eml| from the four non-commented lines that reference it. You can also do this for URL, and LNK
- Then log into WHM, click on Exim Configuration Editor, and change the system filter at the bottom from /etc/cpanel_exim_system_filter to /etc/cpanel_exim_system_filter_custom
- Save the changes
Now Cpanel will use /etc/cpanel_exim_system_filter_custom, which if properly edited to remove the ’eml|’ references in the particular lines will allow EML attachments to go through in the future