smtp发信HELO成功后其他命令502错误

printf("连接成功\n");
        n=recv(s,name,sizeof(name),0);
        name[n]='\0';

        printf("%s\n",name);
        ZeroMemory(name,1000);
        strcpy_s(name,"HELO hi\r\n");

        if(send(s,name,sizeof(name),0)==SOCKET_ERROR)
        {
            printf("发送helo失败%d\n",WSAGetLastError());
        }
        n=recv(s,name,sizeof(name),0);
        name[n]='\0';
        if(n==SOCKET_ERROR)
        {
            printf("接收数据失败%d\n",WSAGetLastError());
        }
        printf("%s",name);

        ZeroMemory(name,1000);
        strcpy_s(name,"auth login\r\n");
        if(send(s,name,sizeof(name),0)==SOCKET_ERROR)
        {
            printf("发送auth login失败%d\n",WSAGetLastError());
        }
        n=recv(s,name,sizeof(name),0);
        name[n]='\0';
        printf("%s",name);