Why does my bot node have a red error triangle on it?

You will see a red triangle on the node if something is missing on your bot path. When you hover the mouse over the triangle you will see a message with suggestions about what to do for resolving the error.
In addition to the red triangle on the node, you will also see an error alert indicator in the More options at the top right corner of the Bot Management page as well.
Clicking on the error text message and you will be automatically sent to the specific node that is causing an error. Most likely, the error is related to the node not being closed. Please see how you can close a bot path in the next answer.