Access denied on all IMCE private files, regardless of profile settings

When using this module, I get "Access denied" errors on all IMCE private files that I try to download. I'm using Drupal-7.50.

It looks like the issue may be occurring in the imce_private_files_simple() and imce_private_files_passthrough() functions in imce_private_files.module as they return either -1 or null, but the Drupal file_download() function expects an array of at least one header, otherwise it will automatically return drupal_access_denied().

Will attach a patch below.