Assign issue based on customfield value

[Connor Sims]

I am trying to assign a user based on a customfield value (If customfield value is West, East, Central, assign to user1, user2, user3)

Customfield is a drop down with 3 options, script is set as a post function as the first in the transition for the Create step and the Open step

Here is my code:

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.MutableIssue

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.MutableIssue

String userName;

switch(ComponentAccessor.getCustomFieldManager().getCustomFieldObjectByName("customfield_10602").toString()){
 case "West": userName = "user1";break;
 case "Central": userName = "user2";break;
 case "East": userName = "user3";break; 
}

issue.setAssignee(ComponentAccessor.getUserManager().getUserByName(userName))

Can someone help me figure out why it keeps going to 'Unassigned' despite saying the post function step succeeded every time?

Many thanks

[BigBrother]

Have you tried using the email addresses as opposed to the user names? When Atlassian rolled out SSO earlier this year, it caused a lot of inconsistencies regarding where usernames are required instead of email addresses and vise-versa.