403 error shows instead the 404 error

Hi all,

What happens:
When you mistype an URL of an event in Maian Events you get a 403 error, not a 404 error because it's a not found.

This doesn't happen if a folder of Maian Events is mistyped (or doesn't exist), the 404 error shows as intended.

Proof of concept:

This event doesn't exist but it shows a 403 error instead the 404 error.

Why it should be fixed?:
In these pandemic days, there are a lot of cancelling events and for Google:

Access denied errors often take the form of a 403 Forbidden response code. When Google returns this error it generally means that the website’s server or host is blocking Googlebot’s access.
These errors are bad for SEO because the search engines can’t crawl that page. If the error isn’t fixed after a certain period of time Google may just de-index the page entirely.

Thanks for your work!