Fix Server Connection Error on Website

I need a professional to help me fix a server connection error that is occurring when I try to launch my website via 'npm start'. The website was working perfectly before, but now I am having issues. I am not sure if any code has been modified since the last successful launch.

Skills and Experience Required:
- Proficient in JavaScript and Node.js
- Experience with website maintenance and troubleshooting
- Familiarity with npm and server connection issues
- Ability to understand and debug code

Please note, I have shared my files via DROPBOX for your reference.