Emails are not being sent from a Plesk server: local data error while talking to smtp.mailchannels.net

Symptoms

• MailChannels SMTP Relay extension is installed

• Emails are not sent from a Plesk server with one of the following messages in /var/log/maillog:

  postfix/smtp[11610]: warning: hash:/etc/postfix/password lookup error for "smtp.mailchannels.net"
  postfix/smtp[11610]: warning: 509F96100CE4: smtp_sasl_passwd lookup error
  postfix/smtp[11610]: 509F96100CE4: to=john_doe@example.com, relay=smtp.mailchannels.net[52.11.68.149]:25, delay=1.7, delays=0.36/0.01/1.3/0, dsn=4.3.0, status=deferred (local data error while talking to smtp.mailchannels.net[52.11.68.149])

  ---

  postfix/error[11351]: 17C23125781: to=john_doe@example.com, relay=none, delay=381781, delays=381781/0.06/0/0, dsn=4.7.1, status=deferred (delivery temporarily suspended: SASL authentication failed; server smtp.mailchannels.net[34.223.183.172] said: 450 4.7.1 Temporary authentication failure. Please try again later.)

• MailChannels SMTP relay serviceis accessible on port 25 via 'telnet':

  # telnet smtp.mailchannels.net 25
  Trying 52.42.188.241...
  Connected to smtp.mailchannels.net.
  Escape character is '^]'.
  220 relay.mailchannels.net ESMTP

Conditions

The "MailChannels SMTP Relay" Plesk extension is not configured.

Resolution

1. Log in to Plesk.

2. Remove or configure the extension.

   • To remove the extension, go to Extension > My Extensions > MailChannels SMTP Relay > Remove.

   • To configure the extension, open it and specify "Username" and "Password" in the fields.

     

     Note: To resend deferred emails, visit this KB article.