How can I use @ to include participant in a comment I want to send Edited

[Skúli Jóhannesson]

I have a task with person A as reporter and I have no problem using the @ in front of the person name in a comment which I want to send to that person. 

However if I also want to send to person B then I can't. I have tried to add person B as a "Request participants" but with no luck. 

Can you help me with this problem?

Br Skúli

[Brant Schroeder]

In order to add someone as a request participant they have to first exist as a customer in JIRA Service Desk.    Just add them as a customer and you will be good to go.  

https://confluence.atlassian.com/servicedeskcloud/adding-customers-852724126.html

[Skúli Jóhannesson]

Hi Brant

Person B was and is a customer.

Br Skúli

[Brant Schroeder]

The are a customer and you can not add them as a request participant.  Can you provide a screenshot.

[Skúli Jóhannesson]

Sorry I am not clear enough. I can add person B as request participant but I can't use the @ sign in front of the name (person B) when I am making a comment on the task and want that comment to be sent to person B also.

[Skúli Jóhannesson]

Can someone help me about this issue (see my comments from March 1st.)

I add a user to the "Request participants" (see first picture) and then try to use that user in the comment field by using @ in front (see second picture)