As the dialogue says it's either damaged or unsupported. Try opening the file in a media player. If it opens then it isn't damaged and the problem is likely compatability. I get that error when my files are not in RGB color space which is required in AE. If you open the file VLC media player go to tools>codec it will tell you.
It looks like it's a clip that was recorded on a DSLR. Is the file still on the memory card and will it play back on the camera?
If it plays as expected on the camera that recorded it, copy it again.
If AE still won't open it and VLC Player won't, try the file in MediaInfo (https://mediaarea.net/en/MediaInfo) to see if you can view what CODEC is being used.
Other applicatons you can try are Telestream Switch (there's a trial version) and DaVinci Resolve.