Upload WordPress Plugin from ZIP Broken – Returns Symbols Squares & question marks

The plugin you are using is perhaps corrupted. With 7-zip or similar archivers on your PC, try testing it, or simply extracting it. If you encounter errors, chances are your downloaded plugin is corrupted.

If not, try removing it from your website, then uploading it again using FTP/SFTP.

Otherwise, contact your plugin support.
Test Archive with 7-zip