Question How to setup a custom error page for my Node.JS App?

[Plesktrum]

Hello Community,

How can I change the default node.js error page ("can't get /url") from server side? The /error_docs folder is filled.
I tried everything I could think of:
-activate/disable nginx proxy option
-setting

proxy_intercept_errors on;

in the additional nginx settings
-explicitly setting error document for nginx and apache
-using nodejs handler to return an error -

app.get('*', (req, res) => res.status(404).send(null))

(that only returned the Chrome error page)

There's no doubt in my mind that I'm not the only one powering a Node.JS website including custom error documents on Plesk
How to do what I wanted?

Best Regards
Plesktrum