[BitBucket user: Stefan Schiele]
[BitBucket date: 2017-11-09.10:12:03]

When I change the file extension to ".json_" the service starts normally. 
Side note: under Windows it's not good practise to put configuration data in the program files folder. Please consider to move this to suggested places, f.e.: 
C:\ProgramData\<Vendor>\
-> Storage location for application data that is to be shared between all users on that computer.
C:\Users\<username>\AppData\
-> Storage location for per-user application data that is exclusive to a user and should not be shared with any other user on that computer.