use rpc method "sigtransfertx" invalid params

[liueleven]

Iuse java sdk send transaction,but return 【{"method":"sigtransfertx","error_info":"invalid params","error_code":1003,"qid":""}】error result

code:

            long amount = 10000L;
            ontSdk.setSignServer(ip+port+"/cli");
            SignServer signServer = ontSdk.getSignServer();
            Object txResult = ontSdk.getSignServer().sendSigTransferTx("ont", from, to, amount, 30000, 0);

why is that?