Screen time red circle on one of my child's account

Help please...

Have two children both iphones...one child (13) no problem with seeing useage, other (16) has red exclamation and 'Screen Time for iphone has not been available for 7 days. Make sire the device is connacted to the internet and is signed in to icloud with x's apple account'.

Please help me as I've asked and seen it's signed in!