Why can't I add a rule?

When you add a rule, you’re telling your bot what to do based on a previous message. The previous message must be connected in the logic flow and be one of the following types: text, number, multiple-choice, or multiple choice (pick one or more). 

The following operations are available for the following message types:

• Text: is, is not, contains, not contains, starts with, ends with
• Numbers: is, is not, is greater than, is less than
• Multiple choice: is, is not
• Multiple choice (pick one or more): is, is not, contains, not contains