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Email authentication issue in Preprod environment



An an outbound email connection is configured to an Mail Transfer Agent (MTA) running on port 25. During testing, a few emails are sent; however, after three to four transmissions an error occurs and the connection is lost.

Error Messages

[ajp-bio-8009-exec-32] [STANDARD] [SBS:01.09.01] (pega_integrationengine_default) ERROR|###.###.###.### user -  Unexpected exception caught while trying to send an email message.
javax.mail.MessagingException: Could not connect to SMTP host:, port: 25;
  nested exception is: connect timed out
    at com.sun.mail.smtp.SMTPTransport.openServer(
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(
    at javax.mail.Service.connect(
    at javax.mail.Service.connect(
    at com.pegarules.generated.SendEmailMessage_071013_liQGQzhEyrJhavvWyarq0A.SendEmailMessage07_10_13(
    at com.pegarules.generated.SendEmailMessage_071013_liQGQzhEyrJhavvWyarq0A.invoke(
    at java.util.concurrent.ThreadPoolExecutor.runWorker(
    at java.util.concurrent.ThreadPoolExecutor$
Caused by: connect timed out
    at Method)
    at com.sun.mail.util.SocketFetcher.createSocket(
    at com.sun.mail.util.SocketFetcher.getSocket(
    at com.sun.mail.smtp.SMTPTransport.openServer(
    ... 72 more

Steps to Reproduce

Configure an outbound email connection to port 25 in Pega Cloud.

Root Cause

AWS as the platform for Pega Cloud has throttled the use of port 25. After a few connection attempts to this port, the port is blocked for some time for security reasons. Similarly, other ports may be affected too.

This can be switched off on demand. However, it is usually only for a defined set of endpoints.

For some endpoints this is switched off by default.

For example,


Perform the following local-change:

Switch off Port 25 throttling in AWS for SMTP MTA address.
Suggest Edit

Published September 22, 2018 - Updated October 8, 2020

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