Excel file is shown as file corrupted while trying to send it as an attachment using AWS Pinpoint service using node

I'm using Amazon pinpoint service to send an email with attachment. It is working fine while sending pdf as the attachment but I'm facing some issue with excel as attachment. The issue is that we are able to receive email in inbox but while trying to open the attachment excel it is showing as file is corrupted and its trying to repair. PFA for more details.

The same file is working fine and we are able to open when we download that file into our desktop. We are using ExcelJs library to generate excel file and then we are uploading them to AWS S3 bucket. We are even able to download our excel file from S3 and its working fine without any issue. But the problem is coming only when we are sending this file through the amazon pinpoint service.