After trying other solutions I found this app does exactly what it is supposed to do. I have dozens of security cameras (various models of indoor and outdoor, with varying features such as pan/zoom and/or two-way audio). Several cameras are at remote locations. This app interacts with all of them nicely.
Take your time setting up your cameras. Follow the camera instructions for updating firmware and setting new secure passwords. Follow your internet router instructions for port forwarding or UPnP if you need access from outside your LAN. Using a dynamic DNS service can be helpful. Make sure your Mac firewall and other settings permit this app to work properly. As with most reasonably powerful apps, there are non-trivial settings. I find that taking enough time to read and follow directions helps.
By the way, I read one review that seems to suggest that positive reviews of this app are being written by people associated with the app publisher. I my case, at least, I have no assocation with the publisher of this app other than being another happy customer.