"The reverse proxy header configuration is incorrect, or you are accessing Nextcloud from a trusted proxy"

[Constrict]

You need to add 172.64.0.0/13 to the ‘trusted_proxies’ in the config. This is a cloudflare IP range with the range of 172.64.0.0 - 172.71.255.255.

<?php
$CONFIG = array (
   'trusted_proxies' => ['172.64.0.0/13'],
);