Hi Shannon30033,
We appreciate you reaching out to us. We understand that your daughter's purchases are being declined even though Family Sharing is set up correctly.
We’d like to gather additional details that may help us be in a better position to assist you.
Is your daughter getting an error message on her device?
Is the issue happening to multiple cards?
Does your daughter have other Apple Pay supported device? For example, an Apple Watch?
If yes, is the issue happening to all devices?
These details can help us in isolating the issue.
Also, we recommend updating your daughter's devices if you haven’t.
While it isn't inherently assured that an update will resolve the issue, updating to the latest version of the operating system for your daughter's device can help isolate potential software issues. Kindly secure a backup and update.
How to back up your iPhone, iPad, and iPod touch
Update your iPhone, iPad, or iPod touch
Update your Apple Watch
Take care!