I was just looking up how to fix this today.
Can confirm that rider99's suggestion works. Adding Shopify registered email address as a confirmed email address on your Paypal account fixes the problem immediately.
Login to Paypal and go to Account Settings > Account Owner Information > Email addresses. Add your Shopify-registered address here and confirm it.
Hope this helps someone else!
I tried rider99's solution and it's still showing the error "A $X USD payment is pending on PayPal Express Checkout." I had a different PayPal email from my store account. I linked the store account email to my PayPal, I tried deactivating and reactivating 2x and it's still not working. Any other solutions? It says it'll be refunded after 29 days. Today is day 28.
I am having this same issue. I had not set up my paypal account prior to the sale but I did immediately after notification so the email addresses are the same for both shopify and paypal. I contacted Shopify who said I needed to contact Paypal. I contacted Paypal who said to contact Shopify. I have been going in circles for 3 hours now! What can I do? I know I shouldn't fulfill the order without payment but I don't know what to do or how to fix it. My shop is brand new and I don't want to upset anyone.
Thank you so much!!!
This totally works. It works the other way too - i had to change my shopify email address to match my paypal business one.
For those whom this hasn't worked make sure you receive confirmation emails and confirm all of these. You WILL also need to deactivate and reactive the paypal setting in the customer payment section of settings.