unable to open downloaded CSV files

For some reason, I am having trouble opening downloaded CSV files in Numbers. I got a popup window that states,"The document could not be opened. You don't have permission." It directs me to check my permissions and I do have read/write permissions. This just started recently, I never had a problem before.

So I updated to Sequoia 15.0.1 and now I I get a popup window that states,"Can't be imported. The file couldn't be opened".

I have a 2019 iMac (model identifier iMac 19,2)

I get the same type of popup with Excel for Mac. It states,"excel cannot open the file "filename.xlsx" because the file format or file extension is not valid.

By the way, if I go to any of my excel or numbers files that are saved, they open just fine.