It just says “File upload fail. Please try again. if you need assistance …”
I’ve tried native windows archive for zip and also 7zip archive as a .zip.
Just to check, you’re only zipping the frontend files, and not any node_modules directories or anything like that, correct? There’s also a size limit (off the top of my head I don’t recall what it is), so check that and ensure you haven’t zipped something excessively large.
Make sure your zip doesn’t include a file with a space in the name. Such as a font file (the common culprit) so just rename the font file and update your includes/paths for that file
Sometimes it could be rejected because of specific files, often fonts.
To identify incompatible files, I see no other solution than removing files or folders progressively until the upload works.