plugin updates failing

Hi,
I have support access on for edielovesmath.net. On this page:
https://edielovesmath.net/wp-admin/admin.php?page=stm-admin-plugins

The plugins are failing to update. Here is the error message one is giving:
Downloading update from https://panel.stylemixthemes.com/api/getpackage/?theme=Smarty&t=e1r2VXUN3qsgzt6whS4KhDxJajeFAMo3&item=stm-importer&ftype=zip…

Download failed. Forbidden