Unable to share shopping list.

My Mum has an echo dot and the Alexa app on her iphone. She tells Alexa what she wants to as to her shopping list and then asks her to send the shopping list to me. This has always worked before but now when my mum asks Alexa she says 'To view or share your shopping list please use the Alexa app' Why has it stopped working?

I have an Alexa app on my phone and my phone is connected by Bluetooth to my mums Alexa app when I’m in the house with her. But I live 200 miles away and it has always sent it to me on my app (which is connected to my own ECHO). I can’t see what’s changed. Any ideas would be greatly appreciated!