Summary

When a user tries to search for others using Basic Search the error message below appears:

"The Jira server was contacted but has returned an error response. We are unsure of the result of this operation."

Grant "Browse users and groups" global permission

This behavior occurs when the user performing the search is not granted the "Browse users and groups" Global permission.

This permission indicates which groups have permission to browse the names of users and groups within Jira. 

To grant this permission to the desired users:

1. Go to  > System > Global Permissions
2. Find permission Browse users and groups to review the groups with this permission
3. Scroll down to the bottom of the Global Permissions page, pick the permission and group, and confirm the update by clicking Add
   1. You can also add the user to one of the groups which already have this permission