PHPJunkyard support forum

I set up Hesk email piping and it seemed to work perfectly but I soon noticed that the pipe would fail with the error message 'local delivery failure' if the email was sent through outlook or any other email client.

I am on a VPS with Cpanel running Centos 5.5.

Here was the solution:

If you have WHM you can go to Software > EasyApache and follow the wizard. In Step 5 click on Exhaustive Options List and check the option for Mbstring. The wizard will then recompile Apache and PHP with the new module.

This fixed it for me and hope it will save someone some time...

Correct, Mbstring is required for email piping as it handles charset conversions.

When you get a "local delivery failed" message you need to check the entire error message as it many times contains a more specific error message.