Nginx Proxy Manager problems

[HenrysCat]

Hi all, I have Freescout running and working well, internally only! when connecting from the outside world it's a different story, seems ok until we try to reply to a ticket, it just says 'Error occurred. Please check your internet connection and try again.' in a red box, then another red box appears 'Lost internet connection' (we can reply to tickets with no issues when connected internally)
I did find this but it's not really relevant to NPM as far as I can tell, is this expected from behind NPM?
Thanks all

[HenrysCat]

After much trial and error I have got this working.

Nginx Proxy Manager settings - Scheme http, port 80, under SSL turn off Force SSL but still create a Let's encrypt cert.

Frescout .env file - add the following lines
APP_URL=https://mydomain.com
APP_FORCE_HTTPS=TRUE
ENABLE_SSL_PROXY=TRUE
NGINX_ENABLE_FASTCGI_HTTPS=TRUE

This got it working externally, to enable internal users to access the site I added a line in the local PC's hosts file pointing to our NPM instance.