PHP & Highcharts Expert Needed for Graph Fixes

I'm experiencing issues with graph rendering on my site, specifically on the Reports page. The graphs are not displaying at all, and there are error messages popping up. I'm not sure what the problem is, but I need a PHP and Highcharts expert to diagnose and fix the issue.

Ideal skills and experience:
- Proficient in PHP
- Experienced with Highcharts
- Able to troubleshoot and fix rendering issues
- Can interpret error messages and diagnose problems

Please provide prior examples of similar work in your bid.