Hi fraser harding, I can reproduce this error only with a fictional phone number like +64 21 121 21212 that is not valid according to the lookup we do with google on the number. In the backend we use a google lookup on the number, hence the rejection and the 400 error. Google is telling us its not a valid number after all.

But on the front end we have a more simple check that could let you type numbers that appear to be real, but are in fact not.

So, there is not really a good solution to this problem at this time.

Is the phone number you used a real working phone number?

on this page

I enter+6421xxxxxx for the phone number,

The images I enter in the License details page, the images upload interface also gives the same cell phone error.

Can you tell me a little bit more about where and when you are seeing this please? Which page of the app? What process are you in the process of performing?

You say the error is related to the MobilePhone number. What is the value you have entered for the phone number?