Hey @dynamiccorvettes
It sounds like checkout is still trying to run Clover logic even though the gateway is disabled. That’s common after a migration because sessions, transients, or a leftover hook can keep pointing to the old gateway.
Start by looking at the real error. In wp admin go to WooCommerce then Status then Logs and open the newest fatal errors log. If you see Clover in the stack, it confirms a leftover hook or file is still loading.
Clear anything that could be “remembering” the Clover gateway. In wp admin go to WooCommerce then Status then Tools and run Clear Customer Sessions and Clear Transients. If you know how to use WP-CLI, this is safe to run wp transient delete –all
Make sure Cash on delivery is truly the only active gateway. Go to WooCommerce then Settings then Payments. Disable everything except Cash on delivery. Open the Cash on delivery settings and check the enable for shipping methods section. If you limited COD to specific shipping methods and the cart’s current shipping method doesn’t match, Woo will show COD in the form but fail at place order. Temporarily remove all restrictions and save.
Force the default gateway to COD so nothing tries to choose a missing Clover method from an old session. Drop this in a small site plugin or your theme’s functions.php and test:
add_filter(‘woocommerce_default_gateway’, function($default){ return ‘cod’; }, 99);
Check for lingering Clover code. Look in wp-content/mu-plugins, wp-content/plugins, and any “code snippets” plugin for anything referencing Clover or clover-payments. A single add_action on woocommerce_checkout_process can throw that generic “error processing your order” even if the gateway is disabled.
Rule out theme or other plugins. Do a quick conflict test by switching to Storefront and leaving only WooCommerce active. If checkout works, re-enable your theme and plugins gradually until the failure returns.
If it still fails, enable debug logging, reproduce the error once, and read wp-content/debug.log. Add this to wp-config.php above the “That’s all, stop editing” line:
define(‘WP_DEBUG’, true);
define(‘WP_DEBUG_LOG’, true);
define(‘WP_DEBUG_DISPLAY’, false);
If you share the exact fatal error or stack from the Woo fatal log or debug.log, we can point to the specific line that’s blocking checkout. Most of the time the fix is either clearing sessions so the old clover gateway id isn’t selected, removing one leftover Clover hook, or loosening the COD shipping restriction so the selected rate matches.