OpenCart 3 + Journal 3 – myPOS Payment Issue

We have two OpenCart websites, haba.bg and ilinor.bg, and we are looking for a reliable OpenCart specialist for long-term technical support when needed. Our current issue is with haba.bg. In May 2026, the store was migrated from OpenCart 2.3.0.2 to OpenCart 3.0.3.6 + Journal 3. Since the migration, myPOS payments have not been completing successfully. Orders are created in OpenCart but remain in Missing Orders, while myPOS confirmed that they do not receive the payment requests from the website. The first task is to diagnose and fix this issue. For the initial diagnostics, we can provide an FTP account restricted to the haba.bg directory, as well as separate access to the OpenCart admin panel if needed. We are looking for a specialist we can continue working with whenever technical assistance is needed for our OpenCart websites.