iPhone 14 pro says phone number from favourites doesn’t exist

[Cojic57]

At times my iPhone 14 says number doesn't exist. The number is in my favourites and is on my emergency call list e.g. partners number. 

it is so frustrating as it doesn't always happen. Our daughter in law who is also with Sky mobile has the message as well at times and it seems it happens at same time - is it a sky network issue or iPhone issue. The iPhone is only 3 months old so it's not as if it's an old phone. The problem has been occurring over the past month or so!!