Please note that a password may be required for various actions on PDF files.
While « viewing » a PDF file might not require a password in your case, most likely « editing » the PDF file will require one (more information can be found here).

Since MailMergic will change the PDF file, we need the password that allows us to edit it.

You’ve got the following options:

• If possible, contact the author of the PDF file and have them give you the password
• Try to make a copy of the PDF file by virtually « printing » it with a PDF printer (such as the free tools 7-PDF or BullZip). You are also welcome to send your PDF to our support so that we can make a copy for you.