When I am trying to assign an incident to someone it's giving me "assignee cannot be set" error

[Sneha Joseph]

So, I am working in this project where the user when trying to assign an incident to themselves, they're getting this error. Although, the users have assign permissions for the jira tickets that would be created once they assign it themselves, they're still getting this error.
I don't know what's happening here!

[John Funk]

Hi Sneha,

Most likely the user is not an Agent - meaning they don't have a Jira Service Management User license. This is needed in addition to a Jira license. 

[Gor Greyan]

Hi @Sneha Joseph

Despite what @John Funk suggests to check, which can be one of the reasons, please also check these points.

•  User has both “Assign Issues” and “Assignable User” permissions

•  Workflow transition doesn’t restrict assignments(Properties)

•  User is an agent (if this is a Service Management project)