Problem in excel email attachment

Hi,
I am using Email.send() for sending excel file with attachments. But getting unable to open attachment in email ->

Email.send({
            to: email,
            from: "xxx@gmail.com",
            subject: "Report ",
            text:'Text',
            attachments: [
              {
                  filename: "report.xlsx",
                  contents: file,
                  encoding: 'binary',
                  contentType: 'application/octet-stream',
                  contentTransferEncoding: 'base64'
              }
            ]
          });

Where as in mailcomposer with nodemailer, it works perfectly. ->

var nodemailer = Meteor.npmRequire("nodemailer");
var transporter = nodemailer.createTransport([smtp]);
        var cid_value = Date.now() + '.image.jpg';
        var mailcomposer = Meteor.npmRequire("mailcomposer");
        var mailOptions = {
            rejectUnhauthorized : false,
            from: "xxx@gmail.com",
            to: email,
            subject: "Report",
            html: html,
            attachments: [
              {
                  filename: "report.xlsx",
                  content: file,
                  encoding: 'binary',
                  contentType: 'application/octet-stream',
                  contentTransferEncoding: 'base64'
              }
            ]
          }
          
 var mail = mailcomposer(mailOptions);
        var stream = mail.createReadStream();
        stream.pipe(process.stdout); 
        mail.build(function(err, message){
            process.stdout.write(message);
        });
        
        transporter.sendMail(mailOptions, function(error, info){
            if(error){
                return console.log(error);
            }
            console.log('Mail sent: ', info);
        });
      }

How to send it correctly

Meteor’s Email package uses mailComposer 0.1.15, which does not seem to support all the options you have used. Perhaps try removing the encoding and contentTransferEncoding options?

I have already tried removing encoding and contentTransferEncoding but that doesn’t work, output is same.