Kivy-android app crashes

I am writing a mobile translator in python kivy. I use the Yandex API. When compiled on windows, the application works correctly. When trying to run on android-crashes after the "Loading" screen saver. How can this be fixed?

Here is my code:

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput
from kivy.uix.label import Label
import requests

URL_AUTH = 'https://translate.yandex.net/api/v1.5/tr.json/getLangs?'
URL_TRANSLATE = 'https://translate.yandex.net/api/v1.5/tr.json/translate'
KEY = '[API ключ]'
LANG = 'en-ru'

# --- Запрос перевода текста
auth = requests.post(URL_TRANSLATE, data={'key': KEY, 'text': 'Translate', 'lang': LANG, }).text

# --- Приложение
class translator(App):

    def translate(self, instance):
        # --- Запрос перевода текста
        auth = requests.post(URL_TRANSLATE, data={'key': KEY, 'text': input_text.text, 'lang': LANG, }).text
        print(auth)
        # --- Обновление текста в Label
        self.output_text.text = str(auth)


    def build(self):
        al = AnchorLayout()
        bl = BoxLayout(orientation='vertical', size_hint=[0.9, 0.9])
        btn = Button(text='Перевести', on_press=self.translate)
        global input_text
        input_text = TextInput(multiline=False, text='Введите текст')
        self.output_text = Label(text=auth)

        bl.add_widget(input_text)
        bl.add_widget(self.output_text)
        bl.add_widget(btn)
        al.add_widget(bl)
        return al

# --- Запуск приложения
if __name__ == '__main__':
    translator().run()