Unable to receive attachments in emails sent

Problem/Motivation

I have a clean drupal 9.3 setup with coc_forms_auto_export module enabled.
Everything works great but emails i receive do not contain any attachment,
i checked on the export path the csv file is properly created after each cron execution.

Steps to reproduce

coc_forms_auto_export,Mail System, and MimeMail enabled
Using Mime Mail as sender and formater in Mail System config

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes