What is this error

[Gordon_Lu]

I think the OP has fed the list socket with a string rather than a list. Show your blocks please.

[New Users] How to ask a question (open new topic)

Before you ask a question / open a new topic please take care of the following points: The forum was previously searched for similar topics / issues. Give a precise (detailed) description of the issue / bug, the goal. Show the (relevant) blocks (images, screenshots of blocks in high quality). Debug your blocks (connect to Companion and right mouse click: → Do it). Name the Android version running on your (test) device. Do not open multiple threads on the same topic. If you haven’t already,…