ICP-8600 Test Monitor Question

I have been using a ICP-8600 test monitor for about a year.  At first I had a lot of issues not being able to get the Onvif to work with any cameras.  Through the last few updates I have had a lot more success.  We have been installing more Hikvision cameras lately and they really seemed to work great with the monitor.  Last week we were able to get into the camera menus and make changes and also look at the picture to make adjustments.  The next day I went to use the test monitor and I was able to get into the menus but I have not been able to get a picture.  Even with the cameras I was able to get pictures the day before, I cannot now.  I have not done any updates to the test monitor or the cameras.  Wondering if anyone else out there uses the test monitor and have had the same problem.  Solutions other than replacing the monitor?