Oracle Cloud Infrastructure - SASL Authentication Failed; Cannot Authenticate To Server smtp.us-$(oci_region).oraclecloud.com[]: No Mechanism Available) (Doc ID 2563337.1)

Last updated on MARCH 08, 2023

Applies to:

Symptoms

Unable to send emails thru Postfix using Oracle Linux on Oracle Cloud Infrastructure 

Error:

Jul 5 21:41:40 localhost postfix/smtp[33732]: SSL_connect:SSLv3 read finished A
Jul 5 21:41:40 localhost postfix/smtp[33732]: Trusted TLS connection established to smtp.us-$(oci_region).oraclecloud.com[<IP>]:587: TLSv1.2 with cipher DHE-RSA-AES256-SHA256 (256/256 bits)
Jul 5 21:41:40 localhost postfix/smtp[33730]: D3F171C0ACA: to=<user1@oracle.com>, relay=smtp.us$(oci_region).oraclecloud.com[<IP>]:587, delay=5896, delays=5896/0.04/0.11/0, dsn=4.7.0, status=deferred (SASL authentication failed; cannot authenticate to server smtp.us-$(oci_region).oraclecloud.com[<IP>]: no mechanism available)  <====HERE
Jul 5 21:41:40 localhost postfix/smtp[33732]: warning: SASL authentication failure: No worthy mechs found  <==== HERE
Jul 5 21:41:40 localhost postfix/smtp[33732]: DB1DD1C0AF0: to=<user1@oracle.com>, relay=smtp.us$(oci_region).oraclecloud.com[<IP>]:587, delay=1339, delays=1339/0.05/0.1/0, dsn=4.7.0, status=deferred (SASL authentication failed; cannot authenticate to server smtp.us-$(oci_region).oraclecloud.com[<IP>]: no mechanism available)

Changes

Configured Postfix on OCI instance using the following KM:

 Oracle Cloud Infrastructure - How To Setup Postfix to Use Email Delivery in Oracle Linux 6 and 7 (Doc ID 2501601.1)

Cause

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