in the current 1553366 chain block 1520998 is 915c0024afd7820a68c9c0c5cd5303314862410bd0d8792fe9959f890fac5db1
You can't get past 1520998 because in your version of blockchain it's different.
To sync to 1553366 you have to delete blk0001.dat and txleveldb dir (or better save them somewhere just in case) and re-download the whole blockchain from scratch.
Maybe there is a fork, not sure. What is the hash of your block 1520998?
Type 'getblockhash 1520998' in debug window.
It seems like something is wrong with PHS anyway, blockchain is stuck at 1553366 for months, mature coins don't stake, network weight is zero.
Probably needs some fix...
ffc7f3c4944ec39d8aad32ceaac5c1e18751068f1f5f8cc1fcd88a3df453b950Type 'getblockhash 1520998' in debug window.
It seems like something is wrong with PHS anyway, blockchain is stuck at 1553366 for months, mature coins don't stake, network weight is zero.
Probably needs some fix...
But it still doesn't work. The download of the blockchain is stuck at around 1520998.
command 'repair wallet' not show any problems