Azure Communication Services
An Azure communication platform for deploying applications across devices and platforms.
Copilot Studio WhatsApp channel binds successfully but Event Grid subscription not auto-provisioned — no inbound messages reach agent
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Sam Maddison
0
Reputation points
I'm trying to connect a Copilot Studio agent to WhatsApp via Azure Communication Services (ACS). The channel binds successfully but no inbound messages reach the agent. After extensive troubleshooting I believe the issue is that the Event Grid subscription which should be auto-provisioned during channel binding is not being created.
Setup
- Azure Communication Services resource with WhatsApp channel registered via the embedded Meta sign-up flow
- WhatsApp channel shows as Active in ACS with display name approved
- Two-step verification configured on the WhatsApp number
- Copilot Studio agent built and published, authenticated via Entra app registration with SSO token exchange
- WhatsApp channel connected in Copilot Studio via Channels → WhatsApp → select Subscription + ACS resource → Save
- Channel shows as connected in Copilot Studio
What is working
- Meta WhatsApp Manager confirms inbound messages are being received
- ACS Event Grid system topic exists with two existing event subscriptions (one for SMSReceived, one for AdvancedMessageReceived pointing at a diagnostic Event Grid Viewer endpoint created during initial setup)
- Event Grid metrics confirm inbound messages are being Published, Matched and Delivered to the diagnostic viewer
- Agent functions correctly in the Copilot Studio test pane (requires sign-in, then responds via configured topics)
- Copilot Studio billing plan is active (pay-as-you-go Copilot Credits) and covers the relevant environment
- Microsoft.EventGrid, Microsoft.BotService, and Microsoft.PowerPlatform resource providers are all registered
- Owner role confirmed on both the subscription and the ACS resource
The problem
When I connect the WhatsApp channel in Copilot Studio, no third Event Grid subscription is created that points at the Copilot Studio agent webhook endpoint. Per Microsoft documentation, this subscription should be auto-provisioned during channel binding.
I have disconnected and reconnected the channel multiple times with 10+ minute waits between attempts, signed out and back into Copilot Studio, hard refreshed the browser, and republished the agent. The auto-provisioning consistently fails to occur and no error surfaces in the UI.
What I cannot do
I cannot create the missing Event Grid subscription manually because the Copilot Studio webhook URL is not exposed in any UI I have been able to locate (Channels, Settings → Security, Advanced agent details, Web channel security). This matches the experience documented in similar Microsoft Q&A threads where this has been confirmed as an internal Microsoft provisioning failure.
Request
Either:
- Guidance on what may be preventing the automatic Event Grid subscription provisioning, or
- The format of the Copilot Studio WhatsApp webhook URL so I can create the Event Grid subscription manually, including any authentication requirements
This is for a business pilot project that is currently blocked. Any guidance appreciated.
Azure Communication Services
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Harshitha Eligeti 10 Reputation points Microsoft External Staff Moderator2026-06-14T20:01:22.0133333+00:00 Hello Sam
It does sound like you’ve done the right “plumbing” checks on the ACS + Event Grid side, and the fact that Meta is receiving inbound WhatsApp messages plus the fact that your existing Event Grid subscriptions deliver to your diagnostics viewer strongly suggests the upstream WhatsApp->Event Grid publishing is working.Based on the information you provided, this specific symptom (“Copilot Studio WhatsApp channel connects successfully, but the expected additional Event Grid subscription that forwards events to the Copilot Studio agent webhook is not created”) aligns with an auto-provisioning failure during the Copilot Studio channel binding flow. Unfortunately, the provided docs don’t include the webhook URL format or any documented way to manually create that Copilot Studio-specific Event Grid subscription.
What you can validate from the docs (ACS side)The ACS “Connecting to Event Grid” guidance recommends verifying that the relevant ACS system topic and event subscriptions exist and checking delivery/endpoint details:
- Confirm the ACS Event Grid system topic exists and has the expected event subscriptions.
- Use Event Subscription / Resource Explorer to inspect endpoint configuration and event types.
- Review delivery metrics (Published/Matched/Delivered) for the event subscriptions you already created.
You’ve already covered many of these, including delivery metrics to your diagnostic viewer, which is a good sign.
What the docs say about manual setup (limits)The “Prerequisites to Configure WhatsApp as a Channel in Microsoft Copilot Studio” article focuses on the required ACS prerequisite work (deploy Event Grid Viewer, subscribe to SMS Received, verify the phone number, etc.) and explains that only after the WhatsApp Business account becomes Active can you link it as a Copilot Studio channel.
However, it does not document:
- the expected naming/creation behavior of the Copilot Studio agent webhook Event Grid subscription, or
- the Copilot Studio WhatsApp webhook URL format (nor its authentication requirements),
- nor any supported manual method to create that Copilot Studio target subscription if auto-provisioning fails.
Best next step (given what you can’t do)
Since your request is specifically “either identify what may prevent auto-provisioning OR provide the webhook URL so we can create it manually,” the provided documentation doesn’t contain the webhook value or the manual instructions needed to proceed safely.
In this situation, the most supportable path is to escalate for investigation with logs from:
- the Copilot Studio channel binding attempt, and
- the ACS/Event Grid provisioning experience during binding (including any relevant activity/diagnostic traces).
The relevant docs also suggest reaching out to the right specialization when provisioning doesn’t work as expected:
- For Event Grid integration troubleshooting, the “Connecting to Event Grid” wiki explicitly recommends involving the ACS Eventing SME or the Event Grid team if unresolved.
- For WhatsApp/Advanced Messaging channel issues in ACS, the troubleshooting article recommends reviewing Azure Monitor/logs and opening a support case if the issue persists.
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