There are NO active masternodes just now...
On page http://sibcoin.org/en/stats in "Masternode" section all of them are in NEW_START_REQUIRED or EXPIRED status.
But the new starting doesn't help!
I have a sense that something in the sentinel's database (sqlite) overloades but I'm not so qualified to track it...

Ivan (ivanr@sib.guru), please take an urgent investigation!