Payment is not working
Check that the correct Stripe API keys are entered and that the extension is enabled.
No order confirmation email is sent
Check the webhook setup. The order confirmation email is normally sent after the order is confirmed.
Webhook is not working
Confirm that the webhook URL is correct, the selected events are enabled, and the webhook signing secret matches the current mode.
Invalid API key error
Make sure you are not mixing test and live keys. Test keys should be used in Test Mode, and live keys should be used in Live Mode.
When troubleshooting, enable Debug Log temporarily, test again, and then review your OpenCart logs.