Hi ,
Welcome to our new Microsoft Q&A Platform.
>>but if fails when I am trying to export FROM 2016 -> 2012
Please try to use netsh command and check if it is successful.
Netsh command:
On the source NPS, open Command Prompt, type netsh, and then press Enter.
At the netsh prompt, type nps, and then press Enter.
At the netsh nps prompt, type export filename="path\file.xml" exportPSK=YES, where pathis the folder location where you want to save the NPS configuration file, and file is the name of the XML file that you want to save. Press Enter.
Copy the file you created to the destination NPS.
At a command prompt on the destination NPS, type netsh nps import filename="path\file.xml", and then press Enter. A message appears indicating whether the import from the XML file was successful.
Best Regards,
Candy