I am sending a message to the Telegram reciver node via telegram. If this message has a fixed content, the function node should pass a string with "1" to the mqtt out node. However, I always get the following error message.
But if i try to inject a string that contains "1" manualy using the inject node, it works fine. I dont know what to do about it.
Have a good read of the node red doc Working with Messages, a little time spent doing that will save you many hours very quickly. Also look through the other documents, Writing Functions in particular. https://nodered.org/docs/user-guide/messages