Error 403 + HTML response from API when trying to create new user

[leonklingele]

Steps to reproduce:

1. Open /settings/users in your browser
2. Create a new user test with password test
3. Receive 403 response from the /settings/users/users API endpoint which returns some HTML:

..
	<li class='error'>
		Zugriff verboten<br>
		<p class='hint'></p>
	</li>
..

Affected version: Nextcloud version 11.0.3 (stable)

I already showed this to @schiessle but we were not able to reproduce this on his machine.
We boiled down the issue to the 'Password rules' options in the admin settings. The issue does not occur when the new user's password fulfills all requirements specified there.

Initially reported by @vaneslie

[rullzer]

Are you running nginx by any chance?
Remove the error_page lines from your config.

[leonklingele]

@rullzer thanks, that fixed the issue. Now the API is properly returning JSON.
The error_page directives were recommended for Nextcloud 10.