iMovie import won't import all files

I'm creating first ever video on iMovie.

I have 17 clips recorded with Quick time player - both movie recording and screen recording. I was able to add first 6 clips and while trying to add next two clips, nothing happens. I am able to add other clips. So the problem is that I can add some, but for some reason not all.

Anyone else had the same problem? How did you solve it out?

I did already try these:

• There is a lot free space on my computer, so that is not the problem (also I can add a 6 min clip but not 1-2 min clip)
• I found an old solution here in the community to delete preferences, did that also, but it did not help. (Tried even twice)

Thanks!

BR

Maarit