iOS: App installed on device can't be found via the search feature

I've got an iPhone 8 running iOS 12.3.1 (latest as of writing).

Recently I've noticed that when I search for an app that is already installed on my iPhone by using the built-in search feature, the app is not found.

The only way I can locate the app is by either manually find it in a folder, or by going to the App Store, searching for it there, then tapping Open.

The app in question is 1Password.

Any idea why the app can't be found? Does it have to do with caching? And if so, how can I clear the cache?

Solution 1:

Go to Settings app → Siri & Search → 1Password and check if Siri & Suggestions is turned off. If yes, turn it on.

Now, the app should appear in search results in Spotlight search.