Invalid domain name

["Luis A. Florit" <mutt-users@xxxxxxxxxxxxxxxxxxxxxx>]

Hi,

    I am using 1.5.16 (2007-06-09), and I've been experiencing the
same problem since I began to use this devel version.

    I am using the built-in SMTP. When I try to send an email
changing the 'From', for example, using this sendhook:

send-hook "~C gimp" 'unset hostname ; set signature= ; my_hdr Reply-to: 
gimpdevel@xxxxxxxxxxxxxxx ; my_hdr From: "Luis A. Florit" 
<gimpdevel@xxxxxxxxxxxxxxx>'

I always get the same error message in mutt:

    SMTP session failed: 501 5.0.0 Invalid domain name

and the message is not delivered. I have 'set use_domain'.

    What is more curious, is that if I postpone the message,
close mutt, open it again, and try to send the same message,
then mutt DOES send the message!

    What am I doing wrong? Has this something to do with
the 'set use_domain'?

    Thanks!!!

        L.