Media Pending. premiere 2020

Hey there. 

I'm editing on a mac book air on Adobe Premiere Pro 2020. When I import the clips into the project window some of the videos 

just hang or they are replaced by the "Media Pending" graphic. This already happens before I take those clips in to the timeline. 

I already cleared the media cache and I also created a sequence and tried disabling and re- enabling clips with no result. 

That's why I thought that the problem has something to do with the import on mac books. I tried to import the clips over the imovie media library but nothing helped. 

Any help or suggestions would be much appreciated 🙂