Unauthorized Exception mainly happends due to two main reasons.
1. Your API Key/Secret Key is wrong
2. Date and time settings of your device are not correct.
I assume that your API Key/Secret Key is correct. Do check the time settings of your device or emulator
Alternately, To ignore time settings on your device go to App HQ Console->App Manager -->view Apps and disable replay attack protection.
Let us know if you still face any problem after the above solutions.