IPN issue

Hello! I have another issue happening now, too.
(the other one is hopefully being addressed-checkout stalling issues on certain items troubles)
The Paypal Merchant Technical Support team told me to contact you for help.

**The only login email address of my current PayPal account is hillbillycollectables@gmail.com. What’s the exact meaning of “PayPal IPN response from a different email address (hillbillycollectables@gmail.com)”?
[this is the exact message: Validation error: PayPal IPN response from a different email address (hillbillycollectables@gmail.com). Order status changed from Pending payment to On hold.}
I have since manually ordered for the customer.
Thank you so much in advance!

The page I need help with: [log in to see the link]