When writing a POP3 client in C

Question

I am working on a simple pop3 client in C, and I had the following problem: In AUTHORIZATION state, the server will never know my password:

Connection successful: + OK GMX POP3 StreamProxy ready

user [e-mail]
+ OK May I have your password, please?

pass ******
-ERR Username or password incorrect

but the same sequence of commands works well in telnet

+ OK GMX POP3 StreamProxy ready
user [e-mail]
+ OK May I have your password, please?
pass ******
+ OK Mailbox locked and ready

I am sure that the password that I am sending is ok. This is how I send the pass command and get a response:

sprintf (command, "pass% s \ r \ n", pass); // pass is the string containing the password
    printf ("% s", command);
    if (write (sock, command, sizeof (command)) == -1)
    {
        fprintf(stderr, "write() error: %d\n", errno);
        return errno;
    }
    if (read(sock, msgbuff, sizeof(msgbuff)) == -1)
    {
        fprintf(stderr, "read() error: %d\n", errno);
        return errno;
    }

.

Answer 1

sizeof (command), strlen () ?