iPhone to iMac videos not recognized

I am baffled. I have the cloud send my photos and videos from my phone to my computer in Photos, and I had been doing it this way for a few years. Then a year or so ago, I updated my mac to the newest OS at the time (can't recall the name of it). I noticed that my uploads were not complete. It would skip several photos and videos. When I would plug in my phone to the computer, it would do the same. I finally got a new computer this past month. It has the latest OS Sierra, and while all my photos are recognized and uploaded fine, NONE of the videos upload. I have searched for answers to this problem and even tried a few, but nothing is working. It is terribly time consuming to try and message videos to myself and then transfer them to Photos by drag/drop. Does anyone know if this is a regular issue or is it just me? Any advice or ideas? I am very frustrated. And no. It is NOT user error.