Warning 15003

WARNING - 15003

Call Progress: Warning Response to Callback URL

Got an HTTP warning in response to the callback URL.

Possible Causes

• Your application returned a 4xx or 5xx HTTP response to Twilio.

Possible Solutions

Ensure your application responds to callbacks with:

• 200 OK
• Content-Type: text/xml
• Valid TwiML

Or respond with 204 No Content and an empty response body.