Fix Server Error 500

I'm encountering a 500 server error on my custom-developed website after updating content. I need an experienced developer to diagnose and fix this issue.

Requirements:
- Experience with custom-developed websites
- Ability to analyze server logs and error messages
- Proficiency in troubleshooting server errors, especially 500 errors
- Access to website's server (full access provided)

Ideal Skills:
- Strong knowledge of web server configurations
- Familiarity with programming languages used in my website
- Problem-solving skills and attention to detail

Please ensure a quick resolution to restore website accessibility.