Going on 8 days now with 7 cores out of 8 grinding ~580 H/m without a single block.
By far this is the hardest coin to mine ever.
check your version and make sure that your always at the updated wallet, after that, everyday check on the node list under "Blockchain" on the wallet, and find ur IP. if your IP doesn't appear there, it might mean that your mining for nothing the past few days. I got pruned off the node list some days ago at 700h/m average and it didn't get me anything as well for days...