Removing the invoice_key parameter from the url after receiving the blank page results in the checkout page being displayed. The error ‘Error: You are not allowed to view this invoice’ appears above the ‘Proceed to PayPal’ button.
The ‘Proceed to PayPal’ button redirects to PayPal correctly.
It looks like W3 total cache is causing an issue. When I disabled it then I don’t see the issue. It may be possible the resources used by W3 total cache are increased or maybe some other issue which exactly you can get from your hosting provider as I don’t see any logs in the WP directory so it might be on the hosting server-side. I have disabled the W3 total cache for now so you can check from your side. If you want to use any other caching plugin then you can use otherwise try to find the exact issue from the hosting provider and let us know so that we can provide you the solution for the same.
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