Overview

This article describes the error and its resolution, which occurs if you are piping emails into Kayako, but your end users are getting a bounce-back email:

******************************************
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients.
This is a permanent error.
The following address(es) failed:
pipe to |/path/to/cli/index.phpgenerated by test@yourdomain.comlocal delivery failed
******************************************

Resolution

You will need to update the exim.conf file to rectify the situation. Open exim.conf and edit the following section:

address_pipe:
driver = pipe
return_fail_output

virtual_address_pipe:
driver = pipe
ignore_status
group = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"
return_fail_output
user = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"

Here, we have changed return_output to return_fail_output.

In case the user's shell is configured as jail shell, you need to suppress the error for jail shell as well i.e.

jailed_address_pipe:
driver = pipe
force_command
command = /usr/local/cpanel/bin/jailexec $address_pipe
return_fail_output

jailed_virtual_address_pipe:
driver = pipe
force_command
command = /usr/local/cpanel/bin/jailexec $address_pipe
user = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"
group = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"
return_fail_output

cagefs_address_pipe:
driver = pipe
force_command
command = /bin/cagefs_enter $address_pipe
return_fail_output

cagefs_virtual_address_pipe:
driver = pipe
force_command
command = /bin/cagefs_enter $address_pipe
user = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"
group = "${lookup{$domain}lsearch* {/etc/userdomains}{$value}}"
return_fail_output

Confirmation

The above shall resolve the email bounce back issue at the client's end.