comment added in particular ticket

[cherry kumar]

whenever the comment added in particular jira ticket then mail should be send to particular user and that user not in the project 

[Fazila Ashraf · Accepted solution]

Hi @cherry kumar

You can add that user to a user custom field of the particular ticket and then add the User custom field value to the 'Issue commented' event. See https://confluence.atlassian.com/adminjiracloud/creating-a-notification-scheme-776636401.html

Make sure that the user has browse permission to the project

[Nic Brough -Adaptavist-]

If a user "is not in the project", then they cannot see the issue, and hence will not get any emails.  You will need to ensure that the user can see the issue, either by being "in the project" or by making the project anonymously accessible.  This is basic security.