JIRA copy with different Assignee between two JIRA systems

[Lan Nguyen]

Source Issue fields:
Some issue field values cannot be copied to the target project.

Assignee:
Following values cannot be copied to the target project:

[Bharadwaj Jannu]

you check whether those fields are assigned to the target project

you check source Assignee user has the permission in target project.

[Lan Nguyen]

We do not have the same set of users (reporter or assignee) between the two systems.

I was able to do remote copy if the reporter and assignee field match.

In our case the users (Assignee and Reporter) between the two JIRA does not match. We have external customer instance then we copy to internal where our developer work on task.