You would need to talk to the administrator of the server to which you submitted the mail for sending. If it is then forwarded to another server for delivery, you'd want to speak to that administrator as well.

A big part of software development is understanding with what your programs interact. In this case, not only do you have a human user but also the SMTP protocol and mail servers. I suggest becoming more familiar with how SMTP email works. The domain knowledge is invaluable to someone writing code for the domain.