MS Teams bot - how to download file that was uploaded in teams

I'm using teams bot api.
We want to support images - a user will upload images in teams bot conversation, and the image will be sent to our server and converted to base64.

The request that my server gets:

{"text":"send file","textFormat":"plain","attachments":[{"contentType":"application/vnd.microsoft.teams.file.download.info","content":{"downloadUrl":"https://*-my.sharepoint.com/personal/*/_layouts/15/download.aspx?UniqueId=2f***b&Translate=false&tempauth=*&ApiVersion=2.0","uniqueId":"*","fileType":"pdf"},"contentUrl":"https://*-my.sharepoint.com/personal/*/Documents/Microsoft Teams Chat Files/myFile.pdf","name":"myFile.pdf"},{"contentType":"text/html","content":"<p>send file</p>"}],"type":"message","timestamp":"2022-07-25T11:13:17.7731472Z"........}

This is my code:

if (message.attachments) {
       const file = message.attachments.find(a => a.contentType === "application/vnd.microsoft.teams.file.download.info");
       if (file) {
             require('request').get({uri: file.content.downloadUrl, encoding: null}, function (err, res, body) {
                if (!err && res.statusCode === 200) {
                    const base64Data = "data:" + res.headers["content-type"] + ";base64," + new Buffer(body).toString('base64'); 
                } else console.log(err ? err : "statusCode: " + res.statusCode);
            });          
       }
}

I'm getting "statusCode: 403".

From the docs it seems like the URL should be public (pre-auth) for a few minutes:

content.downloadUrl is a pre-authenticated link to download the file.
To fetch the contents of the file, send a GET request to the URL in content.downloadUrl. The URL is only valid for a few minutes, so you must fetch the file immediately.

Thanks in advance