Please Help! Cannot access from outside LAN

I’m having trouble trying to fix issues of our company’s NextCloud. We can only access inside the LAN not from the outside. I tried looking at the config.php file and it’s completely blank, empty nothing there. Please help how do I proceed to make the accessable from outside the lan. I’ve been using putty to ssh in the Ubuntu 16.04.4 LTS Server. Please help I’m also some what familiar with linux by no means an expert. Also the ports are forwarded inside the Router.