Sending an excel file to teams bot in a channel

I have made a teams bot using botbuilder SDK 4.0, there is a feature in the bot where the user uploads a file to the bot and the bot collects the download_url and send it to the backend for the file to be downloaded and processed,this is all working fine until i added the bot to a channel.

I can send and receive messages from the bot without any problems but the file upload is not working the file can be uploaded in the channel but the bot does not receive the response and the 'context.activity.attachment.length' is 0, indicating that the bot has not received the attachment.

const url = context.activity.attachments[0].content.downloadUrl;

This is the code i use to get the download url after checking if the attachment.length is greater than 0.

Would appreciate any help in getting the download url for the file uploaded in the teams bot framework.

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