Hola Amigo,
Solo para decirte que yo tenia el mismo error. Lo que hice fue meterme a Google Play, buscar de nuevo el programa "Deliveries" y actualizarlo a la version 4.7.7. Una vez actualizado, reinicia tu telefono y ya funcionará correos de Mexico.
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Hey buddy
Just to let you know that i had the same issue. What i did was enter Google Play search for the app "deliveries" and then update to 4.7.7. Restart your phone and your app will work with correos de Mexico again.
BTW thanks for this awesome APP. very useful for people like us who buy a lot of stuff from asia!