I have a substrate blockchain that was working fine for several months with 4 validator nodes. Then, it was down for 1 month, and when I restarted it, everything seemed to work fine, blocks being produce again, etc.
BUT the blocks where not finalized. I know this is a problem in the long term. I have tried to restart the nodes, to remove and add again some validator nodes. But the blocks are still not finalized.
Here is a link to one of the nodes: https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Frpc-teranyina.centreeasy.com#/explorer
