Here is how to add a custom message to every outgoing email in Roundcube:
Edit the config/default.php file:
nano /usr/local/cpanel/base/3rdparty/roundcube/config/config.inc.php
and add the following to it:
$config['generic_message_footer'] = 'message.txt';
$config['generic_message_footer_html'] = 'message.txt';
Now in root folder of roundcube, create a file named message.txt with the desired content:
-----------------------------
This email was sent from Roundcube cPanel.

![WARNING: [pool user_USERNAME] server reached pm.max_children setting (25), consider raising it Screen Shot 2020 06 23 at 09.57.51 - WARNING: [pool user_USERNAME] server reached pm.max_children setting (25), consider raising it](https://i0.wp.com/administrator.pejcic.rs/wp-content/uploads/2026/09/Screen-Shot-2020-06-23-at-09.57.51.png?resize=344%2C194&ssl=1)

![node[175421]: pthread_create: Resource temporarily unavailable 2023 08 28 12 15 - node[175421]: pthread_create: Resource temporarily unavailable](https://i0.wp.com/administrator.pejcic.rs/wp-content/uploads/2023/08/2023-08-28_12-15.png?resize=344%2C194&ssl=1)