Crash at startup "Missing Module"

Hi,

I’m starting to learn how to develop Apps with Expo. My App works when launched using the QR code, but I tried to build android version and when I run it I get this error:

java.lang.RuntimeException: Expo encountered a fatal error: Requiring unknown module “./locale/es-es”.
at host.exp.exponent.experience.a$2.run(BaseExperienceActivity.java:197)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:6878)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:876)

May you please give me some idea where should I start looking?

Thanks in advance