Have uninstalled and reinstalled, turned off parallel encoding, nothing seems to be working or connecting. I can drag the file in but when I hit Start Queue, it switches to output preview and nothing happens.
Welcome to the joys of being a Beta tester! That's just how it is. Some stuff is not guaranteed to work on Beta builds and since you haven't offered any info on what device you are actually using, your comp contents and so on nobody can tell you more. Start by re-reading the release notes for whatever build you may be using. This may be a known issue. For anything beyond that much more specific info is required.