13238: Dial->Conference: Invalid Verb used in waitUrl, holdUrl, or announceUrl TwiML

The TwiML that executes via the waitUrl, holdUrl, or announceUrl can only contain Say, Play, Pause, and Redirect verbs. Dial, Gather, Hangup and Record are not allowed.

Dial, Gather, Hangup or Record verbs are used in the TwiML.

Remove Dial, Gather, Hangup and Record verbs from the TwiML.