The locktime block of your transaction is 501634 and now it's passed by. Try to use pushtx.btc.com
at the time he broadcasted the tx, the locktime has already passed by.on certain wallet by default locktime is the last block # found at tx sending/relaying time, unless you change it manually
tx info on blockchain.info : Received Time 2017-12-29 21:06:18
Blocks mined : 501634 (Main Chain) 2017-12-29 21:03:36
your tx has OPT-IN RBF , you can try bump the fee if you want
so... what wallet you use? it should have option to create new RBF tx