I get Error initializing Open Alpr when using this sample application

Question

I am trying to use the sample application of this repo.

At some point, I try to recognize a license plate using OpenALPR and I log in Logcat the result :

String result = OpenALPR.Factory.create(MainActivity.this, ANDROID_DATA_DIR).recognizeWithCountryRegionNConfig("eu", "fr", imageFile.getAbsolutePath(), openAlprConfFile, 10);
Log.d("OPEN ALPR", result); 

The result I get is :

{"error":true,"msg":"Error initializing Open Alpr"}

I don't really understand why I get this error.

What I tried :

• Changing the method parameters, using "us" as a country
• Adding android { defaultConfig { ndk { abiFilters "armeabi-v7a" } } } to my build.gradle as related here
• Checking the openalpr.conf to be sure runtime_dir was well setup
• Be sure Open Alpr was loaded by putting a try catch in AlprJNIWrapper when the library is loaded

I tried many other things but nothing make it work.

Any idea?