I’m sorry is not possible, your plugin is installed on a local site in an enterprise server to which can not be accessed from outside. I will carry the problem that occurs when combined with another plugin (Ultimate Members), as already fully discussed on the forum of its creator:
The plugin “Download Manager” causes our $_FILES array to always return empty, so no uploads can be processed (ajax-based).
So please, If you want this resolved, contact the plugin author to fix this conflict, as I can’t do anything to override it from our code. Please understand that not all conflicts can be resolved by editing the plugin code, and some conflicts require the other plugins author attention. So please bring this to their attention as well.
The file that needs $_FILES array access is lib/upload/um-image-upload.php
When that plugin is active, that array is always empty (Which is not true) but works fine when plugin is inactive.
This problem has already been reported to you in this forum, but has never been answered. So, given the needs of the company I work I had (after losing a week in the construction of part of the site) uninstall Ultimate Member and use another solution. All this is very frustrating.