4TB Passport. No desktop/disk space?!?

Hey y’all,
I’m new to this community and hoping someone can help me out. I recently bought a 4TB WD passport HDD. I use it to store video files for my vlog. However, when attempting to copy over files, I got an alert that said there was not enough Desktop space to copy files, and then a separate notification when I tried to pull my folder from the desktop into Passport that said I didn’t have enough Disk space.

I went into the properties of my Passport, and it shows I have over 3TB of space available. Can someone help/inform me as to why I am unable to copy my video files into my Passport if I have this much space available?

Thank you for the feedback!