Follow these steps to verify if the manager can communicate to the SMTP server:

1. Login to your Deep Security Manager (DSM) AMI instance (Linux CLI).
2. Run the following command:

   ping <FQDNoftheSMTP>
   telnet <FQDNoftheSMTP:port> (try the port 25 and 587)

3. Type "helo" or "ehlo" and check if the DSM server can send some request to the SMTP.

   

4. If the session shows you data from the above snippet, then the connection and communication are happening. Refer back to the configuration on the manager side if you miss something out. Refer to the article Configure SMTP settings for email notifications for the configuration.
5. If the connection shows the following entry, proceed to the next set of instructions below.

   

   This is usually caused by the machine not being able to resolve its own hostname before communicating with the SMTP server.

Refer to the overview of SMTP commands, before you proceed:

1. Log in to the DSM machine, execute "hostname" command. Remember the hostname.
2. Execute "ping <hostname>". The hostname is what you got in the first step.

   

3. If the DSM host can't properly resolve the hostname, then please fix this issue using edit /etc/hosts file.
4. Check whether the DSM machine can resolve its hostname. If the issue persist, contact Trend Micro Technical Support for further assistance.