Minecraft error when entering the world?

Hi

I have a world on my phone where I play with my friends. If they come to me it will not work. The others say: "No connection to the world".

But when I go to my friends everything works, even on my mobile phone.

We 3 are always in the same Wi-Fi network in it.

We're also friends at Xbox Live

Who owns the world?

She and my friends saved her on my phone