failed to handshake with xxx: authentication error?

Question

I am trying to use proxy to execute curl command.

I used shadowsocks, I am sure it configured well, because it can use it in my windows laptop.

but it failed when i use it in my centos server.

the command is:

curl -v  -x "user:passwd@ip:8889" "http://httpbin.org/ip"

the server side log is:

failed to handshake with ip: authentication error

the server side config list below:

 {
    "server": "0.0.0.0",
    "nameserver": "8.8.8.8",
    "server\_port": 8889,
    "password": "xxx",
    "method": "aes-256-gcm",
    "timeout": 600,
    "no\_delay": true,
    "mode": "tcp\_and\_udp",
    "plugin": "",
    "plugin\_opts": ""
    }

could you help on this?