I am configuring Sender-Dependent SASL authentication
Were one user will use a smtp relay, We have most of it working exept the authentication to mailgun, we are getting.
E4A8C738106: to=<test@domain.com>, relay=smtp.mailgun.org[198.61.253.48]:587, delay=0.02, delays=0.01/0.01/0/0, dsn=4.7.0, status=deferred (SASL authentication failed; cannot authenticate to server smtp.mailgun.org[198.61.253.48]: no mechanism available)
Made sure we have cyrus-sasl-plain but still getting the error. see error below
> smtp.mailgun.org[198.61.253.48]:587: QUIT
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 220 ak47 ESMTP ready
Aug 30 14:54:23 mail postfix/smtp[23647]: > smtp.mailgun.org[198.61.253.48]:587: EHLO mail.test.com
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250-ak47
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250-AUTH PLAIN LOGIN
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250-SIZE 52428800
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250-8BITMIME
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250-ENHANCEDSTATUSCODES
Aug 30 14:54:23 mail postfix/smtp[23647]: < smtp.mailgun.org[198.61.253.48]:587: 250 STARTTLS
Aug 30 14:54:23 mail postfix/smtp[23647]: smtp_sasl_authenticate: smtp.mailgun.org[198.61.253.48]:587: SASL mechanisms PLAIN LOGIN
Aug 30 14:54:23 mail postfix/smtp[23647]: send attr reason = SASL authentication failed; cannot authenticate to server smtp.mailgun.org[198.61.253.48]: no mechanism available