[SOLVED] Invoice number not updated (caused by cloudflare)

Hi,

I'm using Opencart 2.3.0.2. I've encountered 2 weird data issue.

1. Invoice number is 0 in order table even though payment via payment gateway iPay88 is successful. This order is not listed in Opencart orders page. This is dangerous because I can 't see in orders page, thus overlooked this order. When does invoice number will be populated?

2. There are certain orders with customer ID 0, but fields such as first name, last name, email etc. are populated. What could have caused customer ID not populated?

I've found out these issues are caused by Cloudflare.