If the search results are different from your expectations (e.g. no subtasks found, although there are some) this is usually due to the problems with permission configuration.
In order to perform correctly, the app must have Browse Project and Edit Issues permissions for all projects searched.
Find issues with access problems
If you see that the indexing progress bar has stalled you can identify the problematic issues.
Run this query in Jira Advanced Search to find all issues that are not indexed:
issue.property["jql-search-extensions"].addonVersion.version is empty
The results should identify projects with incorrect permissions scheme. Proceed with the fixes to the schemes documented in the next section. After you’re done with all the projects contact our support to arrange reindexing.
The above query may be slow on large Jira instances. If you’re getting errors:
make sure you run the query in Jira’s Advanced Search and not inside the app
retry the search a few times and each time make sure you wait for a few minutes until you retry
Project Permission Scheme
Find the permission scheme associated with the projects on which the app isn't working correctly (there may be multiple permission schemes to fix for multiple projects).
Project → Project settings → Permissions
Ensure that the project role atlassian-addons-project-access is there. If not, grant Browse Projects and Edit Issue to this project role.