Conversion unsuccessful from PDF to MSCZ

Hello! I am new. I wanted to try and upload a score that my teacher gave me (Attached to this message) to the website but I am unable to convert my PDF to an MSCZ file - when I try it says that the attempt was unsuccessful (I get an email about it too!)

I read some threads online about the same problem and looked at the tips on the conversion page and it looks like my file meets the requirements for the upload.

Can someone please help me figure out why the conversion was unsuccessful? I would appreciate any advice! Thank you!