Limited Access User Lock Down Feature in SharePoint

Most of the time, your search doesn't return any results for anonymous users. To make sure that it does works for them.

please deactivate the feature Lockdown mode.Its is available as a site Collection Feature.

 

Steps

1. Navigate to Site Settings.
2. Under Site collection Admin section
3. Go to Site Collection Features and browse through it and find Limited Access User Lock Down feature.
4. Deactivate it.