I'm at about 56 hours with no Masternode reward... Does this seem normal? I generated 3 rewards previously, all 12-16 hours apart. The node still appears to be running properly, as it was before.
I have 4 masternodes running. One of my nodes will typically only generate a reward every 24-72 hours. Another node I have generates 2-4 rewards daily. This varies over time dependent on the luck of the node. Next week, the under-performing node may be my best and the over-performer may only generate 2 rewards. It's purely luck.
If you flip a coin 5 times and it always lands on heads, there is still only a 50/50 chance it will land on heads the next flip. Same applies to masternode rewards. If there are 600 masternodes online, you will have 1:600 chance of generating each block. Whether it's been 5 minutes or five days since your last block, you still have a 1:600 chance.
There could, however, be issues with your masternode. What VPS do you use? Also, click on the Transactions tab of the wallet. Are you showing that you have generated blocks that aren't accepted? This happens occasionally, but if it happens often then there could be something wrong with your node.