Q: My friends request is not sent to me, but I can send mine to her OK?

Find my Friends issue.

For more details:

Both phones iphone 4S, iOS6.

I can send a request - and accept it on her phone OK without issue - and follow her.

But when I send a request from her phone to mine it never comes to my phone, even though correctly using Apple ID email address.

I have checked settings on both iPhones:

Looking at the Find my Friends troubleshooting guide....

- locations services are on.

- hiding is off on both devices.

- I can find my own device.

- we are connected to Wi-Fi etc

- Notifcations are on.

- there is no junk mail in my inbox.

- I have not exceeded 50 followers

- cellular coverage and wifi signal are all good.

I am on an Australian apple log in, she is on Japanese.

Is this another SoftBank (Japan) quirk?.....

Thanks for any help in advance...