Cannot Generate Code for Mobile Device

I am trying to add cloud access from my mobile phone.

So, from the WD MyCloud Dashboard I choose add a cloud device then I get the Add Cloud Access screen. There is only one user, so I click the Get Code button. When I do this I get the updating… box and then an error message:
Failed to generate code for your mobile device. Please make sure you do not have any network connectivity issues and try again (250005).


As far as I’m aware I do not have any connectivity issues, if I had I wouldn’t be here typing this!


Can anyone give me a clue as to what’s gone wrong?


The solution is here.