Sending mail gets "unknown extension (size 1048576)"

[David M. Karr]

I'm trying to set up this new environment.  I'm unable to send mail.  I
probably have something misconfigured, but the environment sure isn't helping
me figure out what I've done wrong.

When I press C-cC-c, I get the following in the message line:

   unknown extension (size 1048576)

Then the following stack trace:

Signaling: (error "Sending failed; SMTP protocol error")
  signal(error ("Sending failed; SMTP protocol error"))
  cerror("Sending failed; SMTP protocol error")
  apply(cerror "Sending failed; SMTP protocol error")
  error("Sending failed; SMTP protocol error")
  smtpmail-send-it()
  message-send-mail(nil)
  message-send-via-mail(nil)
  message-send(nil)
  message-send-and-exit(nil)
  call-interactively(message-send-and-exit)

The contents of the "*trace of SMTP session to mail.earthlink.net*" buffer:
---------------------
220-snipe.prod.itd.earthlink.net ESMTP Sendmail EL-8_9_3_3/8.9.3; Tue, 13 Mar 
2001 22:50:30 -0800 (PST)
220-NO UCE.  Earthlink Network does not authorize the use of its computers
220 or network equipment to deliver unsolicited electronic mail.
EHLO wondark.earthlink.net
250-snipe.prod.itd.earthlink.net Hello evrtwa1-ar4-004-125.elnk.dsl.gtei.net 
[4.35.4.125], pleased to meet you
250-8BITMIME
250-SIZE 10485760
250-DSN
250-ONEX
250-XUSR
250 HELP
ONEX
250 Only one transaction
XUSR
250 Initial submission
MAIL FROM: <nil>
450 <nil>... Sender domain not compliant with RFC 822, section 6.2.7
QUIT
221 snipe.prod.itd.earthlink.net closing connection

Process SMTP exited abnormally with code 256
---------------------

Various possibly relevant variables:
smtpmail-local-domain:          "earthlink.net"
smtpmail-default-smtp-server:   "mail.earthlink.net"
smtpmail-smtp-server:           "mail.earthlink.net"
mail-host-address:              "earthlink.net"

Recent keystrokes:

RET C-c C-c q C-x b SPC * M C-g C-x b * M C-g C-x b 
SPC C-g C-x b * t r a c e RET C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-x 
b * G RET C-n C-n C-n C-n C-n C-n C-n C-n C-n SPC q 
C-u 1 SPC M-x g n BS BS e m TAB BS BS r e p o TAB r 
t - e m TAB RET


Recent messages (most recent first):

Loading emacsbug...done
Loading emacsbug...
Making completion list...
Making completion list...
Generating summary...done
Generating summary...
Loading gnus-score...done
Loading gnus-score...
Fetching headers for gnu.emacs.bug...done
Fetching headers for gnu.emacs.bug...

-- 
===================================================================
David M. Karr          ; Best Consulting
dmkarr@earthlink.net   ; Java/Unix/XML/C++/X ; BrainBench CJ12P (#12004)