If you attempt to log into the mobile app on your smartphone or tablet you may receive a "JSON parsing error". This error is cause by nonsensical zone settings in TrainingPeaks and can be fixed by logging into your TrainingPeaks account from a computer and fixing your zone settings there. It is most often cause by some running or swimming pace zones being set to "0:00 min/mi or /km". Changing that to a non-zero value should allow you to sign back into the mobile app. Occasionally is caused by other odd zone settings as well, like all of your bike power zones being set to "0-2500 watts".