Permission to Add Comment in an IM Ticket - SD 7.5

Hello,

We have an issue where techs are unable to add comment to an IM ticket and they recieve an error saying "You do not have permission to add a comment to this process". We have modified couple of permissions for the users, however, yet no luck. I guess we are still missing to modify an appropriate permission associated to adding comments.

It would be of great help if someone could share the exact permission that should be modified / enabled so that users are able to add comments. We are on SD 7.5.

Thanks
Snm1502