Usually confirmations, occasionally an underpaid fee.
A deposit that has not credited is almost always waiting on confirmations rather than lost.
The market credits after the network confirms the transaction. Bitcoin can take from minutes to hours depending on the fee. Monero is usually quick. Until the required confirmations land, the balance will not show.
Osiris issues a fresh deposit address per order, so make sure you sent to the address from the correct order. An underpaid Bitcoin fee delays but does not lose the transaction. If confirmations have landed and the balance still does not show, contact market support through the on-site message system with the details.
