Hello,
I deal with the development of ERP projects based on web technology (PHP / jQuery / HTML) and I have developed various web applications for managing multiple online stores or billing and stock management applications. I also deal with optimizing databases for my projects (MySQL), so that they are fast at large volumes of data.
I also develop presentation sites (for which I generally use Wordpress) and online stores (for which I generally use Open Cart).
I am expert in the use and development of Open Cart, having projects developed (and which we still maintain) both in previous versions (version 1.5) and on the latest versions of Open Cart (v 3.x), for which I have developed various designs and modules.
If you want I can check your website to identify and solve the issue, after inspecting a little bit how the error appears and the error_log file. Let's chat before, and we can solve this anytime.
Thank you,
Liviu