The most likely cause for this is that you are trying to spend unconfirmed funds. Unlike bitcoin, the zcash protocol doesn't let you spent unconfirmed funds yet. Please wait for
1-2 blocks for the funds to confirm and retry the transaction.
### Support or other questions
Tweet at [@zcashqtwallet](https://twitter.com/zcashqtwallet) for help.
_PS: zcash-qt-wallet is NOT an official wallet, and is not affiliated with the Zerocoin Electric Coin Company in any way._