Exim Configuration Manager: Advanced Editor does not load

Symptoms

When attempting to load the Advanced Editor of the Exim Configuration Manager, you receive the following error:

directive_matcher could not parse error: [truncated] ... Exim configuration error: new_router "virtual_user" not found for "magicspam_virtual_user" router

Description 

This issue is often related to customizations done by the third-party plugin "Magic Spam", which are not directly supported by cPanel. 

Workaround

Clearing the customizations to Exim can resolve the issue and allow the cPanel interface to load.

1. Access your server using SSH as the root user

2. Move the exim.local configuration file to a backup:

   mv /etc/exim.conf.local{,.$( date +%Y%m%d )} -v

The interface should now successfully load.