E-mail library not properly sending AUTH LOGIN

[eluser]mscahill[/eluser]
I'm attempting to send e-mail through an authenticated SMTP server with CI's e-mail library. I've successfully sent an e-mail with fsockwrite, but cannot do so with CI. Here is the error I get when trying to send an e-mail:

hello: The following SMTP error was encountered: Failed to send AUTH LOGIN command. Error:
from: The following SMTP error was encountered:
to: The following SMTP error was encountered:
data: The following SMTP error was encountered:
451 4.7.0 Timeout waiting for client input
The following SMTP error was encountered:
451 4.7.0 Timeout waiting for client input

Unable to send email using PHP SMTP. Your server might not be configured to send mail using this method.

Any ideas? I can't seem to isolate the point at which the error occurs. Perhaps it's extra characters after the HELO or something...