adding new customers from email CC field from project administrator

[Jan Polanowski]

Hi, can someone help me - I'm trying to figure out the "adding participants from CC field" feature.

Our global configuration is:

Can customers create their own accounts? Yes, by signing up or sending a request

Can customers access and send requests from  the help center without logging in? Yes

Our Jira Service Management project configuration is to accept email requests and:

Choose who can send requests to “$projectname” via $email_addr or the portal: Customers added by agents and admins

At the top of "Customer permissions" configuration page there is a block informing me that:

Agents and project admins can add new customers to a project at any time by including their email address in the "To" or "Cc" field when replying to a request’s email notification.

There is also a page instructing me on how to add new Customers via the CC or TO field https://support.atlassian.com/jira-service-management-cloud/docs/add-request-participants-through-email/

I have a userA in this Service Management project, he has an Administrator role.

When I send an email from userA email address to Service Management email with another, new, user in the CC field - he is not added  as a participant to the request or new Customer.

When I send an email answer (from userA account) to the automatic email and add new user in the CC field - he, again, is not added.

Changing the Choose who can send requests to “$projectname” via $email_addr or the portal:  to Anyone on the web (without logging in) doesn't change anything.

What am I doing wrong?