In some cases, you will receive an error message when you try to send bitcoin, even though it will appear that you have enough bitcoin in your wallet.
This occurs when some of the bitcoin in your wallet was already sent as part of a transaction that is still awaiting confirmation from the network. Thus, the unspent transaction outputs (UTXO) are not yet available to resend as new transactions.
If you recently sent a transaction, and see a balance that you cannot spend, you will see an error message that will state the following:
"Your balance is too low because some transactions are still confirming."
With your Bitwala wallet, it is only possible to send bitcoin if your transaction receives a minimum of three confirmations from the network. It is possible to execute your desired transfer, once the pending transaction has been confirmed.