phpmailer change mail sender

Question

When I send mail from phpmailer and I wanted to response I get response e-mail address like admin@domain.com. But I want change it to office@domain.com. So I added:

Answer 1

Setting Sender is the correct approach to do this, so you're doing that right. The error you are seeing is probably down to SPF checks at the receiver - if the sender domain has SPF set up and it does not allow sending from your IP, it will reject it with the error you are seeing.