Beats Solo 3’s keep turning off

I’ve only had them a couple of weeks but even though the battery is fully charged they keep turning off without warning when i am out walking . I’ve noticed that it only happens when I am in the countryside where presumably internet coverage is not great . It does not happen if i’m in a town centre . Why should they turn off if the internet is poor ? I thought it was all bluetooth . For info I am listening to amazon music via iphone . They can turn off 3 or 4 times during an hour walk so very annoying .