I had the same problem and here’s how I fixed it:
I set up my IPN –
1. Paypal
2. Profile
3. Seller Settings
4. Update IPN Preferences
5. According to WooCommerce you have to use this URL with your website in the example area, for the IPN: https://example.com/?wc-api=WC_Gateway_Paypal
6. I turned off sandbox settings in the WooCommerce Payment Settings under PayPal.
Worked like a charm. hope this helps!
-Arbel
