Unzip error, iPad 13.6 “POSIX error -1 - Unknown error: -1“

Unzip error

POSIX error -1 - Unknown error: -1

I'm trying to UN-compress a 4.7 meg .zip file using the File app in iPad (6th gen), w OS 13.6, to upgrade firmware on my WiFi extender. The file is in my local Downloads folder. There are two ways to do it in the Files app, neither works. I tried searching for a property that has the file locked - that property doesn’t show in Info. 

I get this error "The operation can’t be completed. (POSIX error -1 - Unknown error: -1)" 

Any ideas?