non c’est pas dans le tuto 
voilà ce que donne le mail.log mais je l’effacerais après j’aime pas publier mon domaine sur un forum ^^
May 20 22:03:43 smtp postfix/pickup[6518]: 10BFA1207E4: uid=0 from=<root@smtp.***.fr>
May 20 22:03:43 smtp postfix/pickup[6518]: 10BFA1207E4: uid=0 from=<root@smtp.***.fr>
May 20 22:03:43 smtp postfix/cleanup[7311]: 10BFA1207E4: message-id=<20180520220343.10BFA1207E4@smtp.***.fr>
May 20 22:03:43 smtp postfix/cleanup[7311]: 10BFA1207E4: message-id=<20180520220343.10BFA1207E4@smtp.***.fr>
May 20 22:03:43 smtp postfix/qmgr[6519]: 10BFA1207E4: from=<root@smtp.***.fr>, size=369, nrcpt=1 (queue active)
May 20 22:03:43 smtp postfix/qmgr[6519]: 10BFA1207E4: from=<root@smtp.***.fr>, size=369, nrcpt=1 (queue active)
May 20 22:03:43 smtp postfix/smtpd[7314]: warning: hostname 12-149-172-163.rev.cloud.scaleway.com does not resolve to address 163.172.149.12: Name or service not known
May 20 22:03:43 smtp postfix/smtpd[7314]: warning: hostname 12-149-172-163.rev.cloud.scaleway.com does not resolve to address 163.172.149.12: Name or service not known
May 20 22:03:43 smtp postfix/smtpd[7314]: connect from unknown[163.172.149.12]
May 20 22:03:43 smtp postfix/smtpd[7314]: connect from unknown[163.172.149.12]
May 20 22:03:43 smtp postfix/smtp[7313]: warning: host smtp.***.fr[163.172.149.12]:25 greeted me with my own hostname smtp.***.fr
May 20 22:03:43 smtp postfix/smtp[7313]: warning: host smtp.***.fr[163.172.149.12]:25 greeted me with my own hostname smtp.***.fr
May 20 22:03:43 smtp postfix/smtp[7313]: warning: host smtp.***.fr[163.172.149.12]:25 replied to HELO/EHLO with my own hostname smtp.***.fr
May 20 22:03:43 smtp postfix/smtp[7313]: warning: host smtp.***.fr[163.172.149.12]:25 replied to HELO/EHLO with my own hostname smtp.***.fr
May 20 22:03:43 smtp postfix/smtp[7313]: 10BFA1207E4: to=<kevin@***.fr>, relay=smtp.***.fr[163.172.149.12]:25, delay=0.14, delays=0.04/0.01/0.08/0, dsn=5.4.6, status=bounced (mail for ***.fr loops back to myself)
May 20 22:03:43 smtp postfix/smtp[7313]: 10BFA1207E4: to=<kevin@***.fr>, relay=smtp.***.fr[163.172.149.12]:25, delay=0.14, delays=0.04/0.01/0.08/0, dsn=5.4.6, status=bounced (mail for ***.fr loops back to myself)
May 20 22:03:43 smtp postfix/smtpd[7314]: disconnect from unknown[163.172.149.12] ehlo=1 quit=1 commands=2
May 20 22:03:43 smtp postfix/smtpd[7314]: disconnect from unknown[163.172.149.12] ehlo=1 quit=1 commands=2
May 20 22:03:43 smtp postfix/cleanup[7311]: 3165C1207EB: message-id=<20180520220343.3165C1207EB@smtp.***.fr>
May 20 22:03:43 smtp postfix/cleanup[7311]: 3165C1207EB: message-id=<20180520220343.3165C1207EB@smtp.***.fr>
May 20 22:03:43 smtp postfix/bounce[7317]: 10BFA1207E4: sender non-delivery notification: 3165C1207EB
May 20 22:03:43 smtp postfix/bounce[7317]: 10BFA1207E4: sender non-delivery notification: 3165C1207EB
May 20 22:03:43 smtp postfix/qmgr[6519]: 3165C1207EB: from=<>, size=2301, nrcpt=1 (queue active)
May 20 22:03:43 smtp postfix/qmgr[6519]: 3165C1207EB: from=<>, size=2301, nrcpt=1 (queue active)
May 20 22:03:43 smtp postfix/qmgr[6519]: 10BFA1207E4: removed
May 20 22:03:43 smtp postfix/qmgr[6519]: 10BFA1207E4: removed
May 20 22:03:43 smtp postfix/local[7318]: 3165C1207EB: to=<root@smtp.***.fr>, relay=local, delay=0.03, delays=0.01/0.01/0/0.01, dsn=2.0.0, status=sent (delivered to maildir)
May 20 22:03:43 smtp postfix/local[7318]: 3165C1207EB: to=<root@smtp.***.fr>, relay=local, delay=0.03, delays=0.01/0.01/0/0.01, dsn=2.0.0, status=sent (delivered to maildir)
May 20 22:03:43 smtp postfix/qmgr[6519]: 3165C1207EB: removed
May 20 22:03:43 smtp postfix/qmgr[6519]: 3165C1207EB: removed