The checkout on my WooCommerce store suddenly refuses to process credit / debit card payments—customers reach the final step but the transaction never completes. No error notices appear in WooCommerce logs, and I haven’t changed the plugin, theme, or gateway settings recently. Environment details • WordPress + WooCommerce • Plesk-managed VPS, PHP 8.1, NGINX reverse proxy • Cloudflare active (orange-cloud DNS, “Under Attack” mode occasionally enabled) What I’m looking for 1. Identify the root cause of the “unable to complete payment” issue. 2. Apply a clean, secure fix so card payments succeed again. 3. Verify that PayPal and other gateways remain unaffected. 4. Provide a brief report outlining the fault, the steps you took, and any preventive recommendations (e.g., Cloudflare rule tweaks or additional Plesk settings). Access provided • WordPress admin and Plesk panel credentials • Cloudflare dashboard (if DNS/firewall rules need adjustment) • Staging site on request for testing outside production traffic Success criteria • A live test order processes end-to-end with credit/debit cards. • No new checkout errors for 24 hrs after deployment. • Core files remain untouched; solutions use hooks, settings, or overrides where possible. If you’ve debugged WooCommerce on Plesk/Cloudflare stacks before and can jump on this quickly, I’m ready to grant access right away.