Issues trying to wrap native Android components

Hey everyone,
This is more of an advanced topic but wondering if anyone has come across similar problems.

I’m working on an existing Native app and we are bringing React Native in via pieces of the UI.
As such, there are some cases where we want to wrap native views into React Native.

I’ve tried following all the examples on this React Native docs page, but I keep getting the same kind of error:

Error is of the “Invariant Violation” form such as:

Invariant Violation: requireNativeComponent: “MyViewManager” was not found in the UIManager.

I’m not really even sure how to further debug what is going wrong.
I’ve tried clean builds both Android and JS side.

Any clues?