Power Platform Community Forum Thread Details

I have a Power Automate flow that should track someone putting a checkmark on a thread in Teams.

I use 'When someone reacted to a message in chat'. It generates JSON like this:

{
"type": "OpenApiConnectionWebhook",
"inputs": {
"parameters": {
"reactionKey": "✅",
"frequency": "Multiple",
"runningPolicy": "Everyone",
"threadType": "channel",
"requestBody/channels": [
"Findings-UK"
],
"requestBody/groupId": "a025aff9-71c7-400f-ad3d-be4d455a178b"
},
"host": {
"apiId": "/providers/Microsoft.PowerApps/apis/shared_teams",
"connection": "shared_teams",
"operationId": "WebhookMessageReactionTrigger"
}
}
}



I'm trying to debug why the flow does not trigger. When asking Co-Pilot it indicates the JSON is incorrect. I cannot assess whether that is true.
Your trigger setup looks mostly correct for listening to a specific reaction (✅) in a Teams channel. However, there is a small issue in the JSON:
The property should be "connectionName" instead of "connection" under "host".
Corrected snippet:
"host": { "apiId": "/providers/Microsoft.PowerApps/apis/shared_teams", "connectionName": "shared_teams", "operationId": "WebhookMessageReactionTrigger" }Other than that, your parameters look valid for this trigger. Make sure your Teams connection is authenticated and the group/channel IDs are correct.



Note that I'm using another flow that triggers based on a new threads being started, and that works without issue.

Categories:

Building flows

The problem:



"host": {

  "apiId": "/providers/Microsoft.PowerApps/apis/shared_teams",

  "connection": "shared_teams",

  "operationId": "WebhookMessageReactionTrigger"

}

The fix:

"host": {

  "apiId": "/providers/Microsoft.PowerApps/apis/shared_teams",

  "connectionName": "shared_teams",

  "operationId": "WebhookMessageReactionTrigger"

}

Change "connection" to "connectionName" in the host object.

How to apply this fix:

You need to edit the flow definition directly:

Open Power Automate
Go to your flow
Click the three dots menu, select "Export" > "Package (.zip)"
Extract the zip file
Find the definition.json file
Open it in a text editor
Search for "connection": "shared_teams"
Replace with "connectionName": "shared_teams"
Save the file
Import the modified flow back to Power Automate

Alternatively, try recreating the trigger:

Open your flow in Power Automate
Delete the "When someone reacted to a message in chat" trigger
Add it again fresh
Reconfigure all the parameters (reaction key, frequency, running policy, thread type, channel)
Save the flow

The second approach is faster and less prone to errors. The fresh trigger should generate the correct JSON automatically.

After fixing this, test the flow independently before connecting it back to Copilot Studio. Add a simple action after the trigger (like "Compose" or "Send an email") to verify the trigger fires correctly when you react to a Teams message.