slack worklet keeps hanging on install

I was originally using the slack installer worklet mentioned here:

https://community.automox.com/topic/show?tid=1566&fid=12

But have been running into issues where when the worklet runs, it downloads the installer fine, but when it runs msiexec.exe, it just hangs indefinitely.

If I run this from a powershell command line, it runs fine and installs slack, but hangs in automox. Any ideas what might be going on?

    Start-Process -FilePath 'msiexec.exe' -ArgumentList ('/qn', '/i', $saveFilePath, '/l*v c:\slack.log', '/norestart') -Wait -Passthru