Error handling on pages does not work properly

[Mohamad Berjawi]

Describe the bug
When any page is not found the website will give you a server 500 error.

To Reproduce
Steps to reproduce the behavior:

1. Go to '(https://josa.ngo/events/2565)', or any page that doesn't exist
2. The website will give you a server 500 error

Expected behavior
When a page is not found the website should view the 404 page.

Screenshots