The IPN does not match an existing payment.

My Paypal Standard add-on is now not recognizing payments sent from the Paypal IPN system.  This worked perfectly last year around this time.

According to the logs I'm getting the following:

[07/26/2018 3:04 PM] - SUCCESS!
IPN POST Vars from Paypal:
discount=0.00, insurance_amount=0.00, payer_id=***, address_country_code=US, ipn_track_id=***, address_zip=33018, invoice=8_113, charset=windows-1252, payment_gross=20.00, address_status=confirmed, shipping_discount=0.00, address_street=***, verify_sign=***, item_name=tax appeal, txn_type=web_accept, receiver_id=***, payment_fee=0.88, mc_currency=USD, transaction_subject=, shipping_method=Default, custom=113|***, protection_eligibility=Eligible, address_country=United States, payer_status=verified, first_name=***, address_name=***, mc_gross=20.00, payment_date=13:29:29 Jul 24, 2018 PDT, payment_status=Completed, quantity=1, business=***, item_number=, last_name=***, address_state=FL, txn_id=***, mc_fee=0.88, resend=true, payment_type=instant, notify_version=3.8, payer_email=***, receiver_email=***, address_city=***, residence_country=US,
IPN Response from Paypal Server:
VERIFIED

The IPN does not match an existing payment.

Additionally, I cannot manually add the payment by going to Formidable > Paypal > Add Payments

Has anyone experienced this and know how to get the IPN to match an existing payment to the form entry?