Looks like there is problem with blockchain. Last block 1310273 (4,5 hours ago).
Was coming here to say the same, but I see it's a known thing now. Mine has been behind since Monday, finally synched this morning, now it's back up to over 600 blocks behind.
If you are on block 1310273 then you are in sync. Those 600 blocks you mentiod are probably PoW blocks being generated by miners using old versions of the wallet and will be orphaned once the network resumes normal activity.