Stripe checkout plugin currently has an issue with the webhook not connecting so we took that down until we can figure out what's going on. There is no need for the webhook with the current Stripe plugin since it's all handled on the site (even if you choose the hosted version).  Let me know if this works for you in the meantime and I will keep you updated on the Stripe Checkout version when we have figured out the issue. We are not only working on migrating all the old J2Store J3 plugins over, but about to launch pour first major release 4.1 (which adds several new features and improves the user (and store manager) experiences greatly.