Yes, unfortunately, one of our services is currently experiencing problems. This affects the unlock procedure. Requests come through every now and then (this seemed to have resolved your immediate problem) but most requests for unlock codes are failing.
We are working on a solution. I apologize for the inconvenience. Thanks for your patience.
Edit: To answer your explicit question: There is no offline version for this version of the unlock code. The Settings app needs to contact our backend service to verify the code.