When you try something complicated in Thunkable and it doesn’t work, the best thing to do is to try the simplest form of it you can and see what happens. If that doesn’t work then the more complicated thing won’t work.
So I’m suggesting that you modify these blocks:
Another way to do this is to remove the [convertemailToId] block from the join block and then set the cloud variable to a text string (instead of an object).