The first tip segment in this podcast has to do with making pdf’s in a container field accessible over a WAN (a Wide Area Network). In FileMaker 13 and above, you need to open ports 80 and 443 (SSL). FileMaker 12 and below uses port 16000. So if your pdf’s are disappearing when you upload them over a WAN, check out your ports.
Thu, 30 April 2015
Container Fields remote PDF access, FileMaker writers block, Win 7 on the Mac
Source: Filemaker Success Tips 343