I've been using Channels DVR for about a year I think, and never tried remote access. I'm a bit gun shy of opening up ports on my router. We are going on vacation for a week and I'd like to try out remote access, so just set it up and it went pretty well.
I have an Orbi and followed your instructions here and it didn't work. Then I remember that over 2 years ago when we moved here, I left the AT&T Uverse Gateway firewall on giving me double NAT. I truly didn't remember much about that, but plugged my laptop into the gateway, pointed it at the address. I googled port forwarding for this, and that led me to adding the forward... it was even smart enough to suggest that the Orbi (by device name, not IP address) was what I wanted to forward to. Saved that, and remote access started working. I'm shocked at how easy it was to get going.
Now my fear of safety comes back. Is there any big risk of letting 8089 penetrate my two firewalls to the DVR server, which is a Mac Mini? Anything I should do on the Mac Mini to make sure its safe? Its primarily being used as a dedicated DVR server.
I'm gonna pull the network cables on my QNAP boxes... way to many attacks on them in the news lately.