Google ML Kit: Waiting for the text recognition model to be downloaded

Agree with the answer above that this can happen if the storage on the device is not sufficient or say the internet is not available at all (which seems unlikely given the question). This is a one-time issue faced during development (unless the app cache is cleared).

Just want to add an answer on the manifest meta-tag part. The tag in the manifest avoids this problem in production by pre-downloading the recognition model upon app installation from Play Store:

<meta-data
    android:name="com.google.firebase.ml.vision.DEPENDENCIES"
    android:value="ocr" />

After further investigation, we found that the problem occurs only on a specific device and it coincided with other ad mob anomalies. I tried the following and it works:

Settings->Apps->Google Play Services->Storage->Manage Space->Clear All Data

The first request after that still returned the same error as before, but the second request succeeded.