Debian 8.5 - Postfix - Devcot: setup completed, I get "fatal: unknown service: smtp/tcp"

After a basic sending mail test, the mail did not arrived and /var/log/mail.log records the following lines:

*Jul 13 15:42:14 digitalocean postfix/qmgr[6795]: 3BDABA06EA:, size=406, nrcpt=1 (queue active) Jul 13 15:42:14 digitalocean postfix/smtp[9561]: fatal: unknown service: smtp/tcp Jul 13 15:42:15 digitalocean postfix/qmgr[6795]: warning: private/smtp socket: malformed response Jul 13 15:42:15 digitalocean postfix/qmgr[6795]: warning: transport smtp failure – see a previous warning/fatal/panic logfile record for theproblem description Jul 13 15:42:15 digitalocean postfix/master[6793]: warning: process /usr/lib/postfix/smtp pid 9561 exit status 1 Jul 13 15:42:15 digitalocean postfix/master[6793]: warning: /usr/lib/postfix/smtp: bad command startup – throttling Jul 13 15:42:15 digitalocean postfix/error[9562]: 3BDABA06EA:, relay=none, delay=1016, delays=1015/1/0/0.01, dsn=4.3.0, status=deferred (unknown mail transport error) *

I understand the problem would be “fatal: unknown service: smtp/tcp”. If this is the case, I don’t know what to do in order to fix it. Would you be kind enough to help me? Thanks!

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Update: in the meantime, I followed a third-party link posted by Jon Leibowitz (, and the error got fixed. Short solution: ln -snf /etc/services /var/spool/postfix/etc/services

Now, no errors in /var/log/mail.log, but mails still don’t reach destination eMail address… I will open a new Question.