Hi, I'm French, so first excuse me for my english.

My problem is that I can not send an e-mail to @yahoo.fr.

Here is the message in log (mail.log) :

Sep 23 10:10:31 jeremydevos postfix/smtp[21221]: 93487411BA: to=<jeremy.devos@yahoo.fr>, relay=mx-eu.mail.am0.yahoodns.net[188.125.69.79]:25, delay=0.4, delays=0.01/0.04/0.13/0.22, dsn=4.7.1, status=deferred (host mx-eu.mail.am0.yahoodns.net[188.125.69.79] said: 421 4.7.1 [TS03] All messages from 178.62.55.36 will be permanently deferred; Retrying will NOT succeed. See http://postmaster.yahoo.com/421-ts03.html (in reply to MAIL FROM command)).

With MXTOOLBOX everything is OK :

SMTP Banner Check   OK - 178.62.55.36 resolves to jeremydevos.com
    SMTP Reverse DNS Mismatch   OK - Reverse DNS matches SMTP Banner
    SMTP TLS    OK - Supports TLS.
    SMTP Connection Time    0.905 seconds - Good on Connection time
    SMTP Open Relay     OK - Not an open relay.
    SMTP Transaction Time   3.245 seconds - Good on Transaction Time

Thank you for your help