Outlook direct message not receiving after adding auto forward rule

Hi!

So here's my situation,

The sender(E-mail from a VM) sends every E-mail he receives from a certain E-mail Subject to me(receiver). The auto forward rule works fine and I can receive it properly. Problem is, after assigning the rule, whenever the Sender tries to E-mail me directly, or even if he forward a different E-mail(outside of the auto-forward rule). I can only receive an E-mail from him, if it came from the auto forward rule. 

I am not sure how he set it up on Outlook, I hope you can help me. Thanks.