Do I have to edit the Twitter message?

You have the option to edit the Twitter message within the Attributes section. The content of the Twitter message is automatically generated so you should only edit it if the message exceeds 140 characters. 

If the Twitter message exceeds 140 characters you can still publish the warning and it will publish to all other outputs however the Twitter message won't publish.

Tips on editing the Twitter message so that it is under the character limit are located here.