Thread: Problem implementing POP

Hello,
I'm writing a POP-client, and I have the following problem...
When I connect to any mailserver on port 110, I get +OK and a welcome message. I do

snprintf( buf, 100, "USER %s\r\n", username );
send( s, buf, strlen( buf ) + 1, 0 );

...and I get another +OK, asking for my password.
But when I do

snprintf( buf, 100, "PASS %s\r\n" password );
send( s, buf, strlen( buf ) + 1, 0 );

...i *always* get -ERR Unknown command: PASS. No matter which pop server I try, the PASS command will always work when I connect using telnet, but it always fails when using my client. What's wrong with this?
Thanks in advance.