It tells you why:
"message": "18: bad-txns-inputs-spent"
You are trying to submit transaction that spend an input that is already spent.
The problem is that we didnt try to submit transaction that spend an input that is already spent.
We have more than enough DOGE in the account. and we use listunspent to list the unspent transations.
Yes, indeed. Would you mind to post command you use to create the tx with parameters.