There are a few reasons why employees did not receive their direct deposit. It can either be the bank account information was entered incorrectly or there is a problem with their account. Let me share some insights on how to handle unreceived direct deposits.
You can ask your employees to confirm their correct routing and account numbers with their bank. Typically, the funds will get rejected and returned to your bank account within 2–3 banking days after the pay date.
To request for a direct deposit trace, I'd recommend contacting QuickBooks Online Customer Support Team. They can check its status, verify the reason why their unable to receive it, and can provide to you the trace number that your contractor will use to verify with their bank.