Firebase Functions AppCheck keeps failing my device

I have been trying to integrate AppCheck with my Android app, but I can't seem to make a valid request.

As for test purposes, I have been using the following code:

Android Code

class Application : MultiDexApplication() {

    override fun onCreate() {
        FirebaseApp.initializeApp(this)

        val appCheck = FirebaseAppCheck.getInstance()
        if (BuildConfig.DEBUG) appCheck.installAppCheckProviderFactory(DebugAppCheckProviderFactory.getInstance(), true)
        else appCheck.installAppCheckProviderFactory(SafetyNetAppCheckProviderFactory.getInstance(), true)

        super.onCreate()
    }
}

class TestActivity : Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        val data = "This is a test!"
        Firebase.functions.getHttpsCallable("test").call(data).addOnCompleteListener {
            if (it.isSuccessful) {
                val result = it.result.data
                print(result)
            }

            else {
                val exception = it.exception
                print(exception)
            }
        }
    }
}

Function Code

const functions = require("firebase-functions")

exports.test = functions.https.onCall((data, context) => {
  if (context.app == undefined) {
    functions.logger.error("Test - Failed validating device integrity!")
    throw new functions.https.HttpsError("failed-precondition", "The function must be called from an App Check verified app")
  }

  return data
})

I have added the DebugAppCheckProviderFactory token to the Firebase console, but no matter what I do, if it is an emulator or physical device, when I call the function, the failed-precondition exception is always thrown.

Checking the function logs, I can see that the app is missing:

I have already read the documentation multiple times and I can't seem to be missing any step. Am I missing something or is there anything I can do to find the root cause for this?

Thank you for your time!

from Firebase Functions AppCheck keeps failing my device