For anyone interested in knowing what happened here, OP was using an older version of Parity (1.4.4). Current network requires at least Parity 1.6.10 otherwise you'll risk being on a dead chain. I added this information to the first post. Sorry if it caused problem for anyone.
Yes. I have old install (1.4.4) with old balance.
I mined some coins early at the start. Then left.
Decided to mine again - started parity and ethminer - and it's worked for me.
But it was dead blockchain. Wasted my time for fake mining and writing posts here and in discord ( ...