PayPal IPN Failing

[Merriweather]

I have VB 3.8.1 and I have started receiving the following email from PayPal:

Please check your server that handles PayPal Instant Payment Notifications (IPN).
IPNs sent to the following URL(s) are failing:

http://[removed]/payment_gateway.php?method=paypal

If you do not recognize this URL, you may be using a service provider that is using
IPN on your behalf. Please contact your service provider with the above information.
If this problem continues, IPNs may be disabled for your account.

Thank you for your prompt attention to this issue.


Thanks,

PayPal

The one change I had made prior to this starting was that I had changed my primary email address in PayPal and when I realized my member's payments were no longer activating their accounts, I set the primary email back to what my VB install is using... but I still got another of these emails after doing that.

So... my current API has PayPal as active, and the PayPal Email and PayPal Account Primary Email match the PayPal account settings.

The "Test Communication" check in VB admin says it passed.

What else can I do?