Your fee isn't high enough. Increase the fee in increments of 1 until it goes through. The fee is calculated loosely by the number of transactions incoming to your wallet.
If you made 1 "deposit" of 1,000 XVG, your fee will probably be 1 XVG.
If you made 1,000 "deposits" of 1 XVG, your fee will need to be a lot higher.