"[Filename] is not a directory" when I try to change names en masse with mv?

Question

I am using Ubuntu 16.04 LTS, 64 bit.

I have a folder full of 44 jpeg files with the following naming format—

0094-001.png.jpeg
0094-002.png.jpeg
…
0094-044.png.jpeg

I want to change them all into files with the following naming format—

0094-001.jpeg
0094-002.jpeg
…
0094-044.jpeg

I attempt the following command in the terminal—

mv ./*.png.jpeg ./*.jpeg

I get the following error—

mv: target './0094-044.png.jpeg' is not a directory

Why?