Almost all exchanges require a Memo ID (XLM) or a Destination Tag (XRP) for transactions to successfully be transferred into your wallet.
If you did not include this on the withdrawal, you will have to contact your exchange to see if they can recover your coins.
In order to do this they will need the Transaction ID, which can also be called "Payment ID", "Transaction Hash", "TX: ID" or something similar. You can find it in your Celsius app withdrawal history.
Here are some examples of what the transactions will look like with or without XLM/XRP.
XLM transaction without a Memo ID
XLM transaction with a Memo ID
XRP transaction without a Destination Tag
XRP transaction with a Destination Tag