Although we don't specialize in WordPress development, sometimes we receive the support requests for WP.
For those who have troubles with this error in WooCommerce:
> PayPal error (2): An error (2) occurred while processing your PayPal payment. Please contact the store owner for assistance.
The fix that worked in our case (WordPress version 5.3.2, WooCommerce version 3.9.0 with Jetpack version 8.1.1) was enabling Jetpack plugin, not just on the plugins page, but on the Jetpack page itself:
yoursite.com/wp-admin/admin.php?page=jetpack#/dashboard
You should follow the registration procedure (there's a free plan).
Also
1. You should have PayPal Checkout enabled on your "Payments" tab in WooCommerce config:
yoursite.com/wp-admin/admin.php?page=wc-settings&tab=checkout
2. In PayPal Checkout settings you should see "Payment Email" field in "API Credentials" section - you should put your PayPal email address there:
yoursite.com/wp-admin/admin.php?page=wc-settings&tab=checkout§ion=ppec_paypal
If you follow these instructions it should work, at least it worked for us.