Buildozer return an error when packing pyhton3 to android

See more:

Python3.6

Error message:
# Command failed: /usr/bin/python -m pythonforandroid.toolchain apk --debug --bootstrap=sdl2 --dist_name myapp --name 'Menu Principal' --version 0.1 --package org.test.myapp --android_api 19 --minsdk 9 --private /build/myapp/android/app --orientation sensor --copy-libs --arch armeabi-v7a --color=always --storage-dir=/build/myapp/android/platform/build
#
# Buildozer failed to execute the last command

Command:
kivy@kivyvm:~/menu$ buildozer android debug
# Check configuration tokens
# Ensure build layout
# Check configuration tokens
# Preparing build
# Check requirements for android
# Install platform
# Apache ANT found at /home/kivy/.buildozer/android/platform/apache-ant-1.9.4
# Android SDK found at /home/kivy/.buildozer/android/platform/android-sdk-20
# Android NDK found at /home/kivy/crystax/crystax-ndk-10.3.2
# Check application requirements
# Check garden requirements
# Compile platform
# Build the application #1
# Package the application
# Gradle project detected, copy files /build/myapp/android/platform/build/dists/myapp/src/main/java

Buildozer.spec main configuration:
title = Menu Principal
package.name = myapp
package.domain = org.test
source.dir = .
requirements = python3crystax,kivy
android.ndk_path = /home/kivy/crystax/crystax-ndk-10.3.2/
build_dir = /build/myapp

What I have tried:

I tried to pack a python3/kivy script to android