'trusted_proxies' => ['letsencrypt'],
'overwrite.cli.url' => 'https://nextcloud.your-domain.com/',
'overwritehost' => 'nextcloud.your-domain.com', # 'overwriteprotocol' => 'https',
Add the above lines to config.php just above the line
'dbtype' => 'mysql',
It is important to setup proxynet in unraid as described by spaceinvader one.