Edited a PDF form for users to edit, and now form wont open in email

Hello,

I'm Alex I work IT at a Science R&D company in San Diego, California. One of the projects that I have been working on lately is editing our request forms that we have to make them all on such so users can type on them on their computers, rather than having to print them out and hand write it. I used a software called PDF Converter Professional to add text boxes throughout all the forms. One final task was to add a button to all the forms that would automatically email the form to our help desk once they've completed it. Adding the button to the form was easy, and getting the email sent to our help desk was east as well. However, once we receive the email that has the edited PDF attached to it, we cannot open the file. I'll attach a few images to show you. If you guys could please guide me through what is going wrong and if any solutions are available that would be great.

Thanks

(This happens when we try opening the file after it has been edited)