Try to edit the chainId in your genesis files (Use decimal notation) and this format
(Use no spaces or Quotations "" for chainId)
In toml file:
id = 123
It worth a try.
this will now start behaving as fresh network and I will loose my blocks
If you have changed the chain ID in the genesis.json file, then the blocks from your old network won't be valid on the new network, so you will need to start again.
EIP-155 - which added replay attack protection - has this to say:
If block.number >= FORK_BLKNUM and CHAIN_ID is ...
You can find here an answer for this question (scalability section):