Email attachments problem

When I try to send backup emails from my mikrotik router with attachments through my gmail account the attachments get turned into random characters in the body of the email when I receive it at my other gmail account.

I have another earthlink account I can send the exact same emails through with the mikrotik and receive them with the same gmail account and the attachments are exactly how they should be as files in the attachment field of the email.

I’m using V6.19 ROS

Can anyone help me figure out why this is happening?

Thanks.