WooCommerce checkout fix guides

Checkout broken right now? Start here. Each guide works through the causes in order, with the fix for each.

• WooCommerce checkout not working: how to find the cause
  Checkout spinning, erroring or not placing orders? Find the cause step by step: test it yourself, read the logs, rule out cache, plugins and theme.
• Checkout broken after an update: find the change and roll it back
  WooCommerce checkout stopped working after a plugin, theme or WordPress update? Find which update did it, roll it back safely and stop it happening again.
• Payment method not showing at WooCommerce checkout
  Stripe, PayPal or another payment method missing from your WooCommerce checkout? Check these six causes, from settings and rules to the checkout block.