PHP MySQL 404 Error Fix

I'm encountering a 404 error when trying to access a pages on my application. The database used is MySQL.

Requirements:
- Diagnose and troubleshoot the 404 error
- Fix the php connectivity issues with the MySQL database.

Ideal Skills and Experience:
- Proficiency in PHP and MySQL
- Experience in resolving 404 errors and connectivity issues.
- Familiarity with debugging and server configurations.
- Ability to work within a limited budget.