Can anyone tell me how to solve this?
error: {'message': 'the transaction was rejected by network rules.\n\n16: mandatory-script-verify-flag-failed (Script failed an OP_EQUALVERIFY operation)\n... 'code': 1}
There is the identical case like yours posted in Github, and judging by conclusion of AbdussamadA you can not send coins from your wallet because malware is insert that address in your wallet and you not have private keys to sign transaction. The question that was asked there was : Did you protect your wallet with password?
In short, malware create new address in your wallet - you receive
BTC in this address, and when try to send it you get this error.
It is possible that this is another problem, but it is identical error - read more on this link :
https://github.com/spesmilo/electrum/issues/4462