As achow101 has pointed out, your transaction only included a transaction fee of 0.00005 BTC (that's 0.05 mBTC). Given the current level of bitcoin traffic, if you want your transaction to confirm quickly, a more appropriate transaction fee would have been 0.00052 BTC (0.52 mBTC). Therefore, this transaction paid 0.00047 BTC (0.47 mBTC) less in fees than it probably should have.
There are a variety of ways you could have ended up with an insufficient fee, such as:
- You used a wallet that lets you set your fees, and you chose to set the fee too low
- You used poorly written wallet software that sets the fees for you, and doesn't compute an adequate fee.
- You used software that listens to the bitcoin network to see what the current "typical" fee for fast confirmation is, and didn't give the wallet enough time to discover an appropriate fee.
If you aren't in a hurry, you can just wait. There's a chance that the transaction could confirm sometime in the next few days.
If it doesn't confirm in the next couple of days, then you'll have a few different options on how to deal with the situation depending on what wallet software you are using.
Some wallets (such as blockchain.info) will eventually simply forget that the transaction ever existed. When that happens, they will show the bitcoins that you sent back under your control so that you can try a sending a new transaction.
Other wallest (such as Bitcoin Core) will continue to re-broadcast the transaction forever as long as you leave the software running. It will simply wait forever for the transaction to become confirmed. If you want to give up on the transaction in a wallet like that, then you'll need to take additional steps to tell the wallet to forget the transaction.
I'm not an expert with Electrum, so I'm not sure how your version of Electrum chooses fees, or how to get it to forget transactions. I see that this thread has now been moved to the "Electrum" sub-forum. Hopefully, someone with more Electrum knowledge can help you with the next steps that are available to you.
In the meantime, it would be helpful to know what version of Electrum you are running.