Copilot Studio

SSML audio tag not playing in Conversation Start topic - no sound, no errors

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Posted on by LP-23060804-0

Hello everyone,

I'm trying to play an audio at the start of a call by adding an SSML <audio> tag in the Conversation Start topic:

What I've tried:

Hosted file on Azure Blob Storage (both SAS token and anonymous public access) - URL plays fine in browser
Tried .wav (PCM, 8kHz/16kHz) and .mp3 (16kHz)
Used a self-hosted audio

Result: Complete silence, no errors, no logs anywhere.

Questions:

Is <audio> supported in a normal topic?
Any way to get more detailed logs for SSML/audio failures?
Any undocumented audio format requirements?

Any help appreciated - happy to share more config details.

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General topics

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11manish 4,388 Super User 2026 Season 2 on at

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Based on the symptoms, this appears to be a current platform limitation rather than a configuration issue. There is no documented way to obtain detailed SSML execution logs, and the silent behavior is consistent with an unsupported or ignored <audio> element.

If pre-recorded audio playback is a critical requirement, I recommend opening a Microsoft support ticket.
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Valantis 7,266 Super User 2026 Season 2 on at

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Hi @LP-23060804-0,

fix from Microsoft docs.

The `<audio>` SSML tag only works when the Message node is in Speech & DTMF mode, which requires the Telephony channel to be enabled on your agent. <cite index="73-1">When using the audio src tag, if you store the URL in a variable, encode the URL before inserting it into the audio src SSML tag in the message.

Use the EncodeHTML Power Fx function to encode the URL when assigning it to a variable.</cite>

Two things to check:

1. Is your agent's voice enabled? Go to Settings > Enable voice and make sure it's on. Then confirm your Message node mode is set to Speech & DTMF, not just Text. SSML tags including audio are silently ignored in Text mode.

2. For the audio format: <cite index="79-1">Security scanning code filters out certain values from Azure Blob storage URLs by default when they're passed between systems.</cite> This means the SAS token parameters in your URL may be getting stripped before they reach Azure Cognitive Services. The recommended approach from Microsoft docs is to use static public access or a CDN URL without query parameters, not a SAS token URL for voice SSML.

For the Conversation Start topic specifically: it must also be in Speech & DTMF mode for audio to play. Switch all Message nodes in that topic to Speech & DTMF and add the audio tag in the speech side, not the text side.

Ref: https://learn.microsoft.com/en-us/dynamics365/guidance/resources/copilot-studio-play-audio-file

Best regards,

Valantis ✅ If this helped solve your issue, please Accept as Solution so others can find it quickly.

❤️ If it didn’t fully solve it but was still useful, please click “Yes” on “Was this reply helpful?” or leave a Like :).

🏷️ For follow-ups @Valantis.

📝 https://valantisond365.com/ 💼 LinkedIn ▶️ YouTube
Valantis 7,266 Super User 2026 Season 2 on at

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Hi @LP-23060804-0,

Just wanted to check in and see if everything is working now. If you still need any help, feel free to let me know.

Also, if the issue is resolved, it would be great if you could mark the answer as solved so others with the same question can find it easily.

Thanks and have a great day!