I'm getting this error: creating build on remote server:  itch.io API error (400): /wharf/builds: invalid target (bad user)

This is what I'm typing in: butler push C:\Users\Blake\Desktop\UpdateTestBuild\TestGameV4.zip Blake-McKinnon-Productions/update-test:win

I'm just doing a test update before I update a game that I already have on Itch.io and want to make sure it works correctly without wiping the download count but at the moment I can't get it to work at all.

Any help is much appreciated :)