I have a Github Action workflow where I try to push a build.

In the workflow I download the releases from Github and push them using Butler to itch.io
For all my builds it works, except the HTML-build. 

I get the following error:

butler push "race-the-dots--html5.zip" skar/race-the-dots:html5
> For channel `html5`: last build is 267366, downloading its signature
walking directory to push: zip: not a valid zip file

And that's it. Not sure what's wrong or anything...
When I download this same release to my computer and push locally with this same command, it works as intended.

Anyone any idea what's going on / how to fix this?

Are you sure the file is a valid zip file :). If you’re downloading the file then I’m assuming you’re getting it after it has been placed in as an artifact of the build, so it’s possible you’re trying to run the butler command before the zip file that eventually makes it into build artifacts is ready.

I recommend looking over the order of things to make sure it’s happening as intended. You can also try extracting the zip in CI in place of the butler command to verify that there’s a valid zip file at that path at that time