Sending proactive messages to MS teams in a channel - node.js

Question

We are trying to use proactive messages to send notification in a teams channel whenever some activity happens in the backend system. I am using the below code:
await msadapter.continueConversation(convRef, async turnContext => {
await turnContext.sendActivity('proactive hello');
});
in the above code convRef is a reference to conversationReference that is stored into our database. It is obtained when the first time channel is created using a listener on
this.onConversationUpdate(async (context, next: () => Promise<void>) => {
}
The above technique works just fine when i try it in a group chat. But i get authorization error in case of channel as below
[onTurnError] { Error: Authorization has been denied for this request.
at new RestError (/workspace/node_modules/#azure/ms-rest-js/dist/msRest.node.js:1397:28)
at /workspace/node_modules/#azure/ms-rest-js/dist/msRest.node.js:1849:37
at process._tickCallback (internal/process/next_tick.js:68:7)
code: undefined,
statusCode: 401,
request:
WebResource {
streamResponseBody: false,
url:
'https://smba.trafficmanager.net/amer/v3/conversations/19%3A82de560bf7c843b7a6e050fed39db2c5%40thread.tacv2/activities/f%3A48b6e038-a38d-94e3-7907-dcf88ad4484d',
method: 'POST',
headers: HttpHeaders { _headersMap: [Object] },
body:
'{"type":"message","serviceUrl":"https://smba.trafficmanager.net/amer/","channelId":"msteams","from":{"id":"28:a835cf1d-83a8-4ae9-845a-23a68a1df442","name":"FlashCX.ai"},"conversation":{"isGroup":true,"conversationType":"channel","id":"19:82de560bf7c843b7a6e050fed39db2c5#thread.tacv2","tenantId":"04e930f3-0866-4a6d-b07c-a4737e8f9865"},"recipient":{"id":"29:1a-Xb7uPrMwC2XqjMEHCC7ytV2xb2VUCqTA-n_s-k5ZyMCTKIL-ku2XkgbE167D_5ZbmVaqQxJGIQ13vypSqu-A","aadObjectId":"718ab805-860c-43ec-8d4e-4af0c543df75"},"text":"proactive hello hi","inputHint":"acceptingInput","replyToId":"f:48b6e038-a38d-94e3-7907-dcf88ad4484d"}',
query: undefined,
formData: undefined,
withCredentials: false,
abortSignal: undefined,
timeout: 0,
onUploadProgress: undefined,
onDownloadProgress: undefined,
operationSpec:
{ httpMethod: 'POST',
path: 'v3/conversations/{conversationId}/activities/{activityId}',
urlParameters: [Array],
requestBody: [Object],
responses: [Object],
serializer: [Serializer] } },
response:
{ body:
'{"message":"Authorization has been denied for this request."}',
headers: HttpHeaders { _headersMap: [Object] },
status: 401 },
body:
{ message: 'Authorization has been denied for this request.' } }
Doc reference: https://learn.microsoft.com/en-us/azure/bot-service/bot-builder-howto-proactive-message?view=azure-bot-service-4.0&tabs=javascript#send-proactive-message