I use in my smartphone android Ipcamviewer app. I can see all the cams.
But when I connect Blue IRIS in the PC 4 cams can not see them in the phone. In Blue Iris I can see all them. And when I shut Blue Iris, all the cams works excellent in the phone again.
I'm not sure which cams you have or what your IpCamViewer setup looks like, but I think I had a similar problem with my new 4MP Hikvision. I solved it by changing the channel number (Ch.#) in IpCamViewer for the 4MP camera. I changed from channel 1 to channel 2. The problem camera was a 2T42WD-I8 4MP EXIR IP Bullet.