Show the custom error page

Hello

I would like to how I can try to trigger easily a custom error page set in my tenant setting? I am not able to generate an invalid URL following this doc Customize Error Pages

I always end-up on fallback login page for one of our app.

I tried to copy and /authorize url then in a new window without session, remove some url parameters, but it never show the error page.

Regards

One solution is simply to use outdated password reset link. But if you don’t have one. I am curious about what could be used.