Nextcloud error - JavaScript MIME type .mjs not supported

[folaht]

What app is this about, and its version: Nextcloud 31.0.11
What YunoHost version are you running: 12.1.38
What type of hardware are you using: Raspberry Pi 3, 4+

Describe your issue

I recieve this error in the Nextcloud administration overview.

Share relevant logs or error messages

Your webserver does not serve .mjs files using the JavaScript MIME type. This will break some apps by preventing browsers from executing the JavaScript files. You should configure your webserver to serve .mjs files with either the text/javascript or application/javascript MIME type.

[folaht]

So far I’ve found the following..
Open /etc/nginx/mime.types and change accordingly:

-- application/javascript                           js;
++ application/javascript                           js mjs;

The error still stands though.