Hi @TroyaNO - it looks like you’ve tried to install the discourse-social-share theme component as a plugin. You should remove that line from your app.yml file.
To give some context: Putting a theme in the plugins directory has never worked. But in the past it would fail silently with no error. Over the last 24h or so (since this commit), it started raising an error. I’ve just pushed another change which takes us back to the old ‘silently do nothing’ behaviour, so if you try updating again it should work.