Is your Microsoft Office 32-bit or 64-bit being used with Microsoft Dynamics GP 2015?
The reason I ask is because of the following also mentioned in the GP 2015 system requirements, about PDF not being supported with the 'Exchange' server type, which is required if using 64-bit MS Office with Microsoft Dynamics GP 2015:
NOTES:
1. If using Office x64, the server type in System Preferences
(Microsoft Dynamics GP | Tools | System | Setup | System
Preferences) must be set to Exchange.
2. The Exchange server type only supports XPS and DOCX. PDF is
not supported with the Exchange server type.
3. If using Office 32bit, the server type in System Preferences can
either be MAPI or Exchange
Thanks