13513: Say: Invalid rate value

This warning appears when the rate value inside <prosody> is invalid. Twilio uses a default rate value of 150 when this happens. Twilio supports SSML inside <Say>, but SSML support can vary by provider and voice.

• The <prosody> rate value is malformed or not supported by the selected voice. Twilio supports only a subset of SSML tags, and unsupported SSML can cause <Say> to fail.
• You are using a Basic voice. Basic voices do not support SSML, so <prosody> is not available.

• Change the <prosody> rate value to a supported value, such as x-slow or a percentage like 85%.
• Verify that the selected voice supports SSML and test the TwiML with that exact provider and voice combination before you deploy it.
• If you are using a Basic voice, remove SSML from <Say> or switch to a voice that supports SSML.

• TwiML Voice: <Say>
• Text-to-Speech (TTS)