Randomly getting a status code 500 in Vercel Pro plan.

[XBrewyn]

Page to Investigate

https://easyonlineenglish.vercel.app/

Description

I had a Hobby plan for my Express application, and when I upgraded to the Pro plan, I started randomly getting a status code 500 with MongoDB. I created a new account to test the application with the Hobby plan and did not encounter the status code 500. Is there a way to fix this issue?

1. Hobby plan website: https://easyonlineenglish-eight.vercel.app/
2. Pro plan website: https://easyonlineenglish.vercel.app/

Steps to Reproduce

1. Go to the page Iniciar Sesión.
2. Enter the following credentials: username: test, password: BRewyn12.
3. Open the DevTools and click on the tab named "Console".
4. Refresh the page to obtain the status code 500 (you may need to refresh the page up to 5 times to encounter the error).