TrueNAS - NextCloud - NGINX Configuration

We have a newly installed TrueNAS hosted on premise with NextCloud in a Jail and a reverse proxy NGINX (using certbot for security). We are having issues with http & https login and in particular login loops. We also need to make some advanced reverse proxy configurations to allow it to redirect more than one inbound http/https routes to a second server. Experience of Sonicwall firewalls would also be an advantage.