Hi, without seeing more details about the system or the scan itself I am not sure what is causing it, it could be too few cameras, bad quality of pictures, etc.
But what I have done when I had an issue similar to this one is to select the cameras that didnt align (mostly sure you have some and that is causing this error) and reset them, then align those cameras again. At that time some of those cameras might align but not all. Then repeat the process only with any cameras that are left that could not align. Little by little you can get all the cameras aligned properly and get better results.
Leo