ok. spent more time doing this as it was troubling me. Finally got it working.
Make sure that your VPN connection is working and you are on the home local network. From a web browser on your iPhone or iPad, you can type in the address of the router or the NVR and see if you are able to connect them. I assume you are already beyond this step but wanted to stress anyways.
I gave up on Lorex/Flir Secure app and downloaded FLIR Cloud Client for iPhone. It is much more sophisticated app.
Go to Device Manager.
Click + to Add a Device.
Select DVR/NVR/IP Camera.
Click on Register Mode and select IP address instead of Device ID.
Fill in the IP address, port #35000 (if you haven't changed), password and hit connect! It should work.
Feel free to post your questions.