PDF’s that are compatible with the website PDF compiler are flattened, have no meta data, and have no security or restrictions.  

PDF's that are password protected and are restricted from Compilation or Assembly (Printing) will not be compatible for compiling. This is part of Digital Rights Management (DRM). We will never remove any existing settings or protections from a PDF file. Though the attachment is not compatible to compile in the print, these files can still be uploaded to the system, but will need to be downloaded in order to be viewed - they will not be available via a print of the item. 


If the file has layers or meta data, simply print the file to a New PDF file


This will force a flatten of the file and typically allows the attachment to be compatible with the compiler. 

For more information on how to flatten, remove meta data, and un-restrict files within your PDF Writer, please refer to their resources.