All clips I want to use can upload onto premiere pro if they are the first clip. All subsequent clips will only upload audio. The length of the clip doesn't seem to make a difference. I've been using the same computer for editing for a year or so, so I don't think it's hardware, but I am waiting on an upgrade if that's the issue.
I can still export clips (the single one that uploads), and there is no lag when playing through it, editing, colour correcting, etc. I've tried reinstalling. There was no changes to my settings that I know of.
I understand the problem you are having, but I think we could use a little more information. Could you take some screenshots showing the problem? Could you describe the steps you are taking that lead you to the point where you do not get the expected results? And it's always good to tell us what your computer specs are and what version of Premiere Pro you are using.