When I want to send btc in block chain this message is appearing:
BitcoindException(super=com.neemre.btcdcli4j.core.BitcoindException: Error #-26: 66: mempool min fee not met, code=-26).
Who knows how to resolve this? Can anybody help me please?
It seems to be a known issue on Electrum. Try a different server: https://github.com/spesmilo/electrum/issues/3555#issuecomment-352621941
Some servers set custom min Mempool fee, so the server that blockchain chose has set that option.
In blockchain.info you can't choose custom bitcoin server, So you should get your recovery phrase and import it in electrum since they support this feature. Or you can just wait until that server gets change.