Update to the issue described
above: I've investigated it on the
paid support basis, and discovered that PDF files is not truly the issue here. Uploading a small size PDF went fine, so it was only about PDF file which was about 3.2 Mbytes in size. I've went to PHP info which could be easily produced as:
<?php
phpinfo();
?>
and there it's easy to find 2 major settings which define file uploads:
upload_max_filesize - which has been set just to 2 Mbytes;
post_max_size - which has been to 8 Mbytes.
So, before setting up the max.sizes in the File Bank add-on, at first you should always refer to those settings.
These settings are server-wide, and they couldn't be changed from a PHP script. That means, if in the PHP script you set the max.uploaded size to 5 Mb, but
upload_max_filesize is equal to 2 Mb, and you upload the file which is 3,2 Mb, the file won't be uploaded; and that is, you'll get no infos on it (that's why no REF message is provided in the File Bank).
Only increasing
upload_max_filesize in php.ini on the server makes the bigger files truly allowed for upload. And then, you could rely on this setting to adjust options for max.sizes in the File Bank add-on (as well, in the
File Attachments add-on, too).
Also, keep in mind that
post_max_size, which defines the total size of the post data sent, incl. texts, descriptions, titles, hidden vars and so on, should always be relatively bigger than
upload_max_filesize.