testing SMTP auth via telnet

hi -
I'm trying to get a Eudora 4.3.2 client working
with the SBC Yahoo SMTP server - and it fails -

I can't tell what the AUTH problem is,
as everything looks good from the software client -

So, I'm trying to manually go thru the SMTP handshake via telnet,
and am not sure of how the AUTH info is entered -

---
telnet smtp.sbcglobal.yahoo.com 25
ehlo
auth login
ps@sbcglobal.net <-- sample ID
xyzpass <--- sample pw

----
220 smtp802.mail.sc5.yahoo.com ESMTP
250-smtp802.mail.sc5.yahoo.com
250-AUTH LOGIN PLAIN
250-PIPELINING
250 8BITMIME
334 UGFzc3dvcmQ6
501 malformed auth input (#5.5.4)
535 authorization failed (#5.7.0)