Hi! So, it’s been a while since I encountered this issue, but my suspicion is that you may need to turn off the “wrap u” and “wrap v” options. Or turn off the UV tiling option (I don’t remember which menu that’s in just now, but it wasn’t too hard to find.)
Google is your friend!
Side note: Looks like you’re working with an image that is slightly narrower than the 3D plane. If you edit your image to make it proportional (maybe just add some black bands to the top and bottom), that could take care of the problem as well.