itunes no longer recognizes external hd

I have an external that I keep all my music on. I dragged it over to itunes so it’s on there, but stored on my hd (so I dont take up all the room on my laptop).

For over a year I would just plug in my hd, turn it on, and when I would open itunes everything would play. But now it keeps not finding any of the songs. If I go into the files on my hd and look, I find them; they’re all there. But for some reason it’s not recognizing it like it used to