Which project role should a customer have in order to add a comment to an issue through an email?

[oscar.mora]

Which role should we grant to the customer to be able to add comments to an existing issue through email since we are getting this error?

[Christopher Yen]

Internal comments require a JSM agent license I believe.

This article from Atlassian documents the cause and solution for this issue

https://confluence.atlassian.com/jirakb/comments-via-emails-are-added-as-internal-comments-on-the-customer-portal-1384120766.html

"Summary

Comments made by reporters or request participants via email are added as internal comment.

Cause

A Jira core incoming mail handler/global mail handler is being used by the Service Management project. As described also in this bug, Jira Service Management(JSM) interprets all comments as internal unless:

• They were created in the customer portal
• They were created in reply to an email notification by the reporter / a participant / an agent, and processed by the Service Desk mail handler(Email Channel)
• An agent made a comment in JIRA and selected the "respond to customer" (external) option
• An agent changes any comment from internal to external by editing it in JIRA
• They were created before an existing JIRA project was converted into a Service Desk project

Solution

If you would like to create issues and comments in Jira Service Management projects, it is recommended to use a JSM mail handler rather than a Jira core incoming mail handler/Global mail handler. As JSM mail handler doesn't require users to have a license.

Note: Each Service Management project will have a separate email address for a mail handler. 

For more information on JSM mail handler and core/global mail handler refer to this article."

I have email requests shut off so don't have much personal experience to provide on top unfortunately