How to add "Sender" header

[oleksandrb]

Hi,
I want to add "Sender" header to each delivery sender.
I try to add it in additional headers but it won't add.
I can add other additional headers.
Any ideas

 

[twisted1919]

You can try to set "Force Sender" to Always in the delivery server settings, but that might break delivery. Other than that, there's no other way.