What are you waiting for?
A waiting payment has been shared but has not yet been included in a block. Once included, it has a confirmation. Blocks added afterwards give it further confirmations and make changing that history harder.
Someone can ask for a payment to reach their own confirmation requirement before treating it as complete. That policy is separate from the moment your wallet first shows the payment.
Why can payments wait differently?
Imagine a busy waiting room for payments. Miners choose which valid payments to put into proposed blocks. Fees can affect that choice, and new blocks do not arrive on a timetable.
A payment with a low fee may wait while other payments are included. Choosing a higher fee does not create a guaranteed deadline. A service may also delay sending or crediting a payment for its own reasons.
What can you check?
Look at whether the payment has actually been sent, whether it is waiting for a block and how many confirmations the recipient requires. If a service account is involved, distinguish its processing time from the network's confirmation progress.
Do not treat a screenshot saying “sent” as proof that the recipient has a confirmed payment. Check the status in the wallet or record you are using.