Hi
Sushanta,
You can set up the email server and change it in the UI, you just need go to admin > System and license management, when you see your deploy (Console, collectors, events procesor) open the console it will be open in a pop up window and you can see in the last tab the email server option, just click on it and set or change your email server.
If this don't work you can try using the qchange_netsetup command, you must use this command in the VM using the root user.
Hope it work to you, regards
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Johan Lopez
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