You need administrator rights in Jira to perform the tasks on this page.
When you create a new Checklist custom field, the search template is set to Checklist Searcher by default to ensure that checklists are searchable. However, if you are running an older version of Checklist for Jira, your custom field may not have a search template set.
To set the search template to Checklist Searcher:
Go to Administration > Issues.
In the sidebar, go to Fields > Custom fields.
In the Actions column, click the menu icon for a specific Checklist custom field and click Edit.
Click the Search Template drop-down and select Checklist Searcher.
Re-index Jira to ensure that your existing checklists will be updated.