WooCommerce checkout page customized incorrectly: why did fields or layouts break?
Checkout and cart issues in WooCommerce usually affect add-to-cart behavior, field validation, totals, or final order submission. Merchants should verify whether the problem is frontend rendering, server processing, or a checkout customization conflict.
Cart and checkout can break because of cache, incompatible extensions, custom field changes, or performance bottlenecks that interrupt submission. A gateway problem can also look like a generic checkout issue if the final step fails silently.
Use the official checkout troubleshooting guide first, then run conflict testing if the problem began after a customization or plugin change. If the checkout still fails, collect logs and exact reproduction steps so you can isolate whether the issue is visual, validation-related, or payment-related.
Official URLs to review: