Dear MMDs,  A great thanks to the six people who took time to answer
my posting.  It proves that there is a real problem which annoys many
people around the world.

You may read the anti-spam ATT policy on the following web page:
  http://www.att.net/general-info/mail_info/block_enduser.html

ATT asks you to contact your provider, but don't waste time doing so
and writing to your provider, because it will not answer.

When ATT (and apparently a few other American providers) refuse _all_
messages from another provider, because they say too much spam comes
from it, there seems to be only three solutions:

(1) Subscribe with an alternative provider to send to ATT, as I did:
it may work for some time, until ATT finds this provider sends too
much spam ...

(2) Ask your ATT correspondent to have a second free e-mail address,
independent from ATT -- that would be the best way!

(3) Or use the standard ground postal service, or the fax.

We'll keep in touch if we find better solutions.

Kind regards,
Philippe Rouillé (Paris, France)
http://www.musicamecanica.org/