I can't add second video file

Hi there! I got an issue with adding a second video to my timeline,

I add a video, then I want to add another one on the V2 track, it's "locked/blocked"

I select the file from the project panel and drag it to the timeline, but it only changes my cursor to a "first with a something like a stop sign"

P.S Thanks in advance, hope some of you might know the solution!