Blue Iris

The camera number is right there in your image three fields below the user field. Doesn't that change the url?

Oh, and if your above screenshot does give an image, try changing that "11" to an adjacent integer. Experimentation may solve this. You can always clone the working "camera" so you don't lose the settings.

It would be helpful if you could provide the model number of the DVR/NVR..., maybe a pic of the main screen after you've logged in also. It's highly unlikely it was made by Tenvis or Foscam. Narrowing down the manufacturer may help to determine the actual convention used for the stream addresses.

The stream address also needs to have the desired camera channel number entered. It should auto-populate after entering the channel in the box and saving the settings but will default to 1 if not saved first with a different channel number. Try a different channel in the box, then save the configuration and see if the new channel number is still there and is also now in the the main stream URL.

Also see if there are other entries in the pulldown menu of the main stream. There may be others listed for successive channels that simply need to be checked accordingly for each additional camera channel. The same should be true for the sub streams.

They are TH661 cameras. Through the browser and the app I can switch fine. It's just Blue Iris that only detects the main camera 1.

Under Stream profiles only "default" is listed. Not a list sadly.

Changing the Cam # just shows the same camera again.

I've tried changing the 11 in the stream url but seems to do the same. Think I may luck out here.

Is there no NVR and you are just setting these up as independent cameras with the app to view with Blue Iris? Or someone else did?

They can be set up a variety of ways, both wireless and wired. Read the following for a fairly comprehensive overview of what they can do and how to make them do it.

https://www.mbreviews.com/tenvis-th661-review/

If relying on Blue Iris as the main NVR, each camera will need to be configured for the existing network and given its own IP address -- preferably as addresses specifically registered to each camera from your router's dhcp server...., if there's not another NVR or server in the mix somewhere.

I guess the bottom line question is, what are you plugging the cameras into?

The plot thickens...

Or we're simply victims of an easily amused fisherman.