Copilot Studio – WhatsApp Channel (ACS) returns SystemError on every inbound message

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Posted on by VR-30120950-0

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I’m using Copilot Studio with the WhatsApp channel via Azure Communication Services.
Status

BYON phone number: Active
QR Code: Works
WhatsApp channel deployed successfully
Event Grid topic and webhook subscription auto-created by Copilot Studio

Issue: Every inbound WhatsApp message returns:
“Sorry, something unexpected happened. Error Code: SystemError. Conversation ID: …”

This happens immediately and for all messages. No bot logic is executed.

Question: What causes a SystemError at runtime for the WhatsApp channel?

Specifically:

Where can I see detailed logs for inbound WhatsApp message processing?
Does this error indicate a failure between ACS → Event Grid → Copilot Studio?
Are there runtime requirements (permissions, identity, networking) not validated during channel deployment?

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Valantis 6,735 on at

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Hi @VR-30120950-0,

Here's whati found on the issue:

SystemError is a generic error in Copilot Studio with no specific root cause shown.

Check this:

ACS Advanced Messaging Logs (Azure Monitor) - shows if WhatsApp messages are coming in properly

Event Grid diagnostic logs - confirms if events are reaching the Copilot webhook

Copilot Studio Application Insights - shows if the message actually reaches your agent

Make sure your agent is published and auth is set to "No authentication" or "Authenticate manually" (WhatsApp requirement).

To pinpoint the issue, share these 3 things:

A failed message entry from ACS Advanced Messaging Logs

The Event Grid delivery log (shows success/failure + reason)

Whether the same message appears in Application Insights for your agent

This will tell us exactly where it's breaking (ACS, Event Grid, or Copilot).

Microsoft's official fix is to contact Support with logs, so we need to check where exactly it's failing.

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Valantis 6,735 on at

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Hi @VR-30120950-0,

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!

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Ronan Vico 6 on at

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I have the same issue...

Almost 2 weeks and cant achieve the WhatsApp Channel publish.

ACS is OK. EventSubscription is OK. I can send message through ACS. Copilot is OK. No Auth. Tryied everything , raised a ticket at microsoft, nothing works.

I Think this channel just Doesnt work , cant find anyone that achieve it ,

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