Problem in sending mail with attachement
For sending mail with attachment you should use Mail System and Mime Mail module
Attachment functionality is built into the Mime Mail module.

After that you must set up drupal_mail() to use mime mail as the mail system interface. This is where the mail system module comes into play. The module is pretty straightforward, and lets you set a different mail system per module. There is a straightforward configuration at admin/config/system/mailsystem where you create a new setting for your module, and select mime mail as the mail system.

Assing anttatcment in variable

$message['params']['attachments']


After that you will be able to send mail with attachment.

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