Copilot Studio WhatsApp not responding - Event Subscription provisioning failure

Question

Copilot Studio WhatsApp not responding - Event Subscription provisioning failure

Victor Daniel Tomás Rodríguez 5

I am using a Copilot Studio agent connected to WhatsApp via Azure Communication Services (ACS).

Current state:

Agent is published

Authentication is set to No authentication

WhatsApp channel is connected successfully (Status Active - Number verified)

Inbound WhatsApp messages are received by ACS (confirmed)

Issue:

The agent does not send any response

Event Grid System Topic is created and in Succeeded state

No Event Subscription is created

System logs show:

Write SystemTopic EventSubscription: Started → Accepted → Failed

Expected: When publishing the agent, the Event Grid event subscription should be automatically created and forward incoming messages to Copilot Studio.

Actual: The subscription provisioning fails internally, so messages are never delivered to the agent.

Additional context: This issue has occurred before, and at that time it was confirmed to be an internal Microsoft provisioning issue and was resolved on your side.

Request: Please investigate and fix the internal provisioning failure during publish, ensuring the Event Subscription is correctly created so WhatsApp messages can reach the agent.

Praneeth Maddali 12,670 Reputation points Microsoft External Staff Moderator

2026-06-08T05:46:36.0666667+00:00
Hi @Victor Daniel Tomás Rodríguez

Thank you for the detailed information — this really helps narrow down the issue.

The behavior you're describing is consistent with a known intermittent failure during Event Grid Event Subscription provisioning when publishing the WhatsApp channel in Copilot Studio. ACS is correctly receiving messages and the System Topic is created, but the subscription needed to forward events to your agent isn't being provisioned.

How the flow is supposed to work

WhatsApp > Azure Communication Services > Event Grid (System Topic + Event Subscription) > Copilot Studio agent.

Because the Event Subscription is missing, incoming messages never reach the agent, so it appears unresponsive.

Steps to Resolve

Validate Prerequisites & Permissions

Make sure the account you're using has Owner permissions at the Azure Subscription level (Contributor is often insufficient).

Confirm the Microsoft.EventGrid resource provider is registered in your subscription.

Reconnect & Re-publish the Channel (Recommended First Step)

In Copilot Studio, go to your agent > Channels > WhatsApp (ACS).

Disconnect the channel.

Wait 5–10 minutes.

Reconnect the same WhatsApp number and re-publish the agent.

This usually forces a fresh provisioning attempt and resolves the missing subscription.

Verify the Event Subscription After republishing:

Go to your Azure Communication Services resource > Events.

Check that an Event Subscription now exists under the System Topic.

Manual Event Subscription (if reconnecting doesn't work) You can create the subscription manually:

In the ACS resource > Events > + Event Subscription.

Event Types: AdvancedMessageReceived (and related messaging events).

Endpoint Type: Webhook.

Endpoint: Copy the webhook URL from your Copilot Studio WhatsApp channel settings.

Authentication: No authentication.

Reference :

https://learn.microsoft.com/en-us/azure/communication-services/concepts/advanced-messaging/whatsapp/whatsapp-channel-prerequisites

https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/advanced-messaging/whatsapp/handle-advanced-messaging-events

https://learn.microsoft.com/en-us/microsoft-copilot-studio/publication-add-bot-to-whatsapp

Kindly let us know if the above helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.
Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-08T11:31:18.9566667+00:00

Hi @Praneeth Maddali ,

Thank you for your detailed guidance.

I have already validated all the prerequisites mentioned:

I have Owner permissions at the subscription level.

The Microsoft.EventGrid provider is registered.

This setup has been reviewed multiple times.

I have also performed step 2 (disconnect and reconnect the channel) several times, waiting between attempts, but the behavior remains the same (the Event Subscription is still not being provisioned).

Regarding the manual workaround (step 4), I’m unable to proceed because no webhook URL is available in Copilot Studio for the WhatsApp channel. It appears the webhook is not being generated at all, which aligns with the missing Event Subscription.

Additionally, the configuration is set with no authentication, as expected.

At this point, it seems the issue is not related to configuration on my side but rather a failure during the provisioning process.

This is currently blocking the solution, so I would appreciate if you could help escalate or provide further guidance on how to force the webhook/subscription creation or diagnose why it is not being generated.

Thank you in advance for your support.
Praneeth Maddali 12,670 Reputation points Microsoft External Staff Moderator

2026-06-09T04:27:57.2766667+00:00
Hi @Victor Daniel Tomás Rodríguez

Thanks for the thorough update I appreciate you confirming the prerequisites and retrying the disconnect/reconnect steps multiple times. Sorry this is still blocking you; it does sound like an internal provisioning hiccup preventing the Event Subscription (and thus the webhook) from being created automatically.

Quick Workaround to Get It Working

Even when the webhook URL isn't immediately visible in the channel settings, you can usually find it here:

In Copilot Studio, open your agent > Channels > select the WhatsApp (ACS) channel.

Look under Advanced settings, Callback information, or the connection details section for the webhook/callback URL (it often follows a pattern like https://*.botframework.com/api/v1/bots/... or ends in /api/updates).

If it's still not showing, try:

Going to the Microsoft Copilot Studio Admin Center (powerplatform.microsoft.com) and reviewing the channel configuration there.

Republishing the agent once more after a short wait.

Once you have the URL, manually create the Event Subscription in your Azure Communication Services resource:

Go to your ACS resource > Events > + Event Subscription.

Name: Something like copilotstudio-whatsapp.

Event Types: Select Microsoft.Communication.AdvancedMessageReceived (and IncomingMessageReceived if available).

Endpoint Type: Webhook.

Endpoint: Paste your Copilot Studio webhook URL.

Authentication: No authentication.

Add an advanced filter for your specific WhatsApp phone number/channel ID (highly recommended).

You can also do this via Azure CLI for precision.

After creating it, the subscription should go to Succeeded. Send a test WhatsApp message and check the agent's responses and Event Grid delivery metrics.

Reference :

https://learn.microsoft.com/en-us/microsoft-copilot-studio/publication-add-bot-to-whatsapp

https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/advanced-messaging/whatsapp/handle-advanced-messaging-events

https://learn.microsoft.com/en-us/azure/communication-services/concepts/advanced-messaging/whatsapp/whatsapp-channel-prerequisites

Kindly let us know if the above helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.
Praneeth Maddali 12,670 Reputation points Microsoft External Staff Moderator

2026-06-10T06:12:39.8533333+00:00

Hi @Victor Daniel Tomás Rodríguez

Just following up to see if your issue has been resolved or if you had a chance to review my earlier comment?
Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-11T13:28:48.2966667+00:00

Hi @Praneeth Maddali ,

I cannot find any webhook/callback URL. I searched on all the parts that you said and doesn´t show any
Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-19T09:05:54.81+00:00
Hi @Praneeth Maddali,

Thank you for the continued support, but the suggested solutions do not apply to this case.

To clarify what has already been confirmed and attempted:

Already done, no change:

Disconnect/reconnect performed multiple times, with waiting periods between attempts

Owner permissions confirmed at subscription level

Microsoft.EventGrid resource provider is registered

No webhook/callback URL exists anywhere in Copilot Studio for this WhatsApp channel - not in Advanced settings, not in channel details, not in the Power Platform Admin Center

Root cause (confirmed): The Event Subscription is not being provisioned automatically during publish. The system logs show: Write SystemTopic EventSubscription: Started → Accepted → Failed. Because the subscription is never created, no webhook is generated.

Log error automatic provisioning: The automatic deploy itself returns: Webhook endpoint validation failed. Error: Check Access failed for Resource.

Manual creation attempts also failed: We attempted to create the Event Subscription manually using the following webhook URLs:

https://europe.whatsapp.botframework.com/api/v1/bots/<id>

https://powerplatform.com/{id}/bots/{bot-id}/runs

Both attempts failed. The subscription could not be validated.

Historical context: This exact issue occurred before on this same tenant. At that time, I opened a support ticket, and one day the automatic provisioning started working on its own. I did not change anything on my side. This confirms it is an internal Microsoft provisioning issue that requires action from the engineering team.

We are requesting escalation to investigate and fix the provisioning failure so the Event Subscription is correctly created automatically on publish.
Praneeth Maddali 12,670 Reputation points Microsoft External Staff Moderator

2026-06-23T04:53:14.8466667+00:00
Hi @Victor Daniel Tomás Rodríguez

Apologies for delay

Thank you for the detailed update and for confirming all the steps you've already tried — I appreciate how thoroughly you've documented this. It's clear this goes beyond standard configuration, especially with the recurring "Webhook endpoint validation failed. Error: Check Access failed for Resource" and the historical behavior on your tenant.

The "Check Access failed" error during Event Grid subscription validation typically means Event Grid's initial handshake call to the webhook endpoint isn't completing successfully (often due to transient routing/identity resolution issues or the endpoint not being fully ready during auto-provisioning). Since the webhook URL isn't surfacing in Copilot Studio either, the automatic flow is getting stuck early.

Targeted Next Step: Force a Clean Manual Subscription via Azure CLI

To bypass the auto-provisioning hiccup, let's try creating the subscription with more control:

First, retrieve the exact webhook URL (even if hidden):

In Copilot Studio, republish the agent once more.

Check the Power Platform Admin Center > Environments > [Your Environment] > Channels (or search for the bot's connection details).

Then run this in Azure CLI (replace placeholders):
az eventgrid event-subscription create \ --name copilot-whatsapp-sub \ --source /subscriptions/{subscriptionId}/resourceGroups/{rgName}/providers/Microsoft.Communication/communicationServices/{acsResourceName} \ --topic-name {systemTopicName} \ --endpoint https://europe.whatsapp.botframework.com/api/v1/bots/{your-bot-id} \ --endpoint-type webhook \ --included-event-types Microsoft.Communication.AdvancedMessageReceived \ --advanced-filter "data.channelId" StringIn "['your-whatsapp-channel-id']" \ --no-auth

This ensures the right event type and adds a filter for your WhatsApp number. Monitor the provisioning status and Event Grid delivery metrics right after

Reference:

https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/advanced-messaging/whatsapp/handle-advanced-messaging-events

https://learn.microsoft.com/en-us/azure/communication-services/concepts/advanced-messaging/whatsapp/whatsapp-channel-prerequisites

https://learn.microsoft.com/en-us/microsoft-copilot-studio/publication-add-bot-to-whatsapp

If this still fails with the same validation error, it strongly points to an internal provisioning issue on our side (consistent with what resolved spontaneously last time).

Kindly let us know if the above helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.

Your answer

Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-08T11:31:18.9566667+00:00

Hi @Praneeth Maddali ,

Thank you for your detailed guidance.

I have already validated all the prerequisites mentioned:

I have Owner permissions at the subscription level.

The Microsoft.EventGrid provider is registered.

This setup has been reviewed multiple times.

I have also performed step 2 (disconnect and reconnect the channel) several times, waiting between attempts, but the behavior remains the same (the Event Subscription is still not being provisioned).

Regarding the manual workaround (step 4), I’m unable to proceed because no webhook URL is available in Copilot Studio for the WhatsApp channel. It appears the webhook is not being generated at all, which aligns with the missing Event Subscription.

Additionally, the configuration is set with no authentication, as expected.

At this point, it seems the issue is not related to configuration on my side but rather a failure during the provisioning process.

This is currently blocking the solution, so I would appreciate if you could help escalate or provide further guidance on how to force the webhook/subscription creation or diagnose why it is not being generated.

Thank you in advance for your support.
Praneeth Maddali 12,670 Reputation points Microsoft External Staff Moderator

2026-06-10T06:12:39.8533333+00:00

Hi @Victor Daniel Tomás Rodríguez

Just following up to see if your issue has been resolved or if you had a chance to review my earlier comment?
Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-11T13:28:48.2966667+00:00

Hi @Praneeth Maddali ,

I cannot find any webhook/callback URL. I searched on all the parts that you said and doesn´t show any
Victor Daniel Tomás Rodríguez 5 Reputation points

2026-06-19T09:05:54.81+00:00

Hi @Praneeth Maddali,

Thank you for the continued support, but the suggested solutions do not apply to this case.

To clarify what has already been confirmed and attempted:

Already done, no change:

Disconnect/reconnect performed multiple times, with waiting periods between attempts

Owner permissions confirmed at subscription level

Microsoft.EventGrid resource provider is registered

No webhook/callback URL exists anywhere in Copilot Studio for this WhatsApp channel - not in Advanced settings, not in channel details, not in the Power Platform Admin Center

Root cause (confirmed): The Event Subscription is not being provisioned automatically during publish. The system logs show: Write SystemTopic EventSubscription: Started → Accepted → Failed. Because the subscription is never created, no webhook is generated.

Log error automatic provisioning: The automatic deploy itself returns: Webhook endpoint validation failed. Error: Check Access failed for Resource.

Manual creation attempts also failed: We attempted to create the Event Subscription manually using the following webhook URLs:

https://europe.whatsapp.botframework.com/api/v1/bots/<id>

https://powerplatform.com/{id}/bots/{bot-id}/runs

Both attempts failed. The subscription could not be validated.

Historical context: This exact issue occurred before on this same tenant. At that time, I opened a support ticket, and one day the automatic provisioning started working on its own. I did not change anything on my side. This confirms it is an internal Microsoft provisioning issue that requires action from the engineering team.

We are requesting escalation to investigate and fix the provisioning failure so the Event Subscription is correctly created automatically on publish.