Twilio IVR integration

Hello,
I have configured channel for Twilio Voice, then published it. I have also configured Twilio according to the instructions in Kore.ai docs and channels part. Still when I call my bot, Twilio gets following error:
11205 - HTTP connection failure

Could you please help me figure this out?

Resolved by configuring ‘Default Conversation’ ‘Welcome Telephony Event’ in Natural Language menu.