problems with Runtastic

TRD66

I've been trying to register for this but when I enter my date of birth (in the correct format) I get an error message to say I need to be 13 to register. Now I'm way past 13 and I've tried my own birth date and a couple of random dates as well, but the same error message. This isn't the first time I've had this problem.

Anyone else had it? If so, what did you do about it?