Не реагирует на нажатия телеграмм бот

Я написал бота на телебот и сделал инлайн клавиатуры, я новичок в телеботе и до конца не понял как работает call_back, у меня есть меню: Смотреть новости/Настройки. При нажатии на любую все отлично, если я перехожу в настройки, то там еще одна клавиатура, но при нажатии на нее ничего не происходит.

import telebot
from newsapi import NewsApiClient
from telebot import types
bot = telebot.TeleBot('токен')
newsapi = NewsApiClient(api_key='токен')
language_var='ru'
category_var=''
country_var=''
@bot.message_handler(commands=["start"])
def main_menu(message):
    markup=types.InlineKeyboardMarkup(row_width=1)
    markup.add(types.InlineKeyboardButton('Смотреть новости',callback_data='CheckNews'),
               types.InlineKeyboardButton('Настройки', callback_data='Settings'),
               )
    bot.send_message(message.chat.id, text='*Меню:*', reply_markup=markup,parse_mode="Markdown")
@bot.callback_query_handler(func=lambda call:True)
def news_settings_handler(call):
    if call.data=='Settings':
        settings_markup = types.InlineKeyboardMarkup(row_width=1)
        settings_markup.add(types.InlineKeyboardButton('Язык', callback_data='Language_settings'),
                   types.InlineKeyboardButton('Категория', callback_data='Category_settings'),
                            types.InlineKeyboardButton('Страна', callback_data='Country_settings'),
                   )
        bot.send_message(call.message.chat.id, text='*Настройки:*', reply_markup=settings_markup, parse_mode="Markdown")

        @bot.callback_query_handler(func=lambda call: True)
        def settings_handler(call):
            if call.data == 'Language_settings':
                language_markup = types.InlineKeyboardMarkup(row_width=1)
                language_markup.add(types.InlineKeyboardButton('Русский', callback_data='ru'),
                                    types.InlineKeyboardButton('Английский', callback_data='en'),
                                    types.InlineKeyboardButton('Немецкий', callback_data='de'),
                                    types.InlineKeyboardButton('Назад', callback_data='back')
                                    )
                bot.send_message(call.message.chat.id, text='*На каком языке вы хотите читать новости?*',
                                 reply_markup=language_markup,parse_mode="Markdown")
                @bot.callback_query_handler(func=lambda call: True)
                def language_handler(call):
                    global language_var
                    if call.data=='ru':
                        language_var='ru'
                    elif call.data=='en':
                        language_var='en'
                    elif call.data=='de':
                        language_var='de'
                    elif call.data=='back':
                        main_menu(call.message)
            elif call.data == 'Category_settings':
                category_markup = types.InlineKeyboardMarkup(row_width=2)
                category_markup.add(types.InlineKeyboardButton('Спорт', callback_data='sport'),
                                    types.InlineKeyboardButton('Бизнес', callback_data='business'),
                                    types.InlineKeyboardButton('Развлечения', callback_data='entertainment'),
                                    types.InlineKeyboardButton('Общее', callback_data='general'),
                                    types.InlineKeyboardButton('Медицина', callback_data='health'),
                                    types.InlineKeyboardButton('Наука', callback_data='science'),
                                    types.InlineKeyboardButton('Технологии', callback_data='technology'),
                                    types.InlineKeyboardButton('Все категории', callback_data='Default'),
                                    )
                bot.send_message(call.message.chat.id, text='*Какие новости вы хотите читать?*',
                                 reply_markup=category_markup, parse_mode="Markdown")

                @bot.callback_query_handler(func=lambda call: True)
                def category_handler(call):
                    global category_var
                    if call.data == 'sport':
                        category_var = 'sports'
                    if call.data == 'business':
                        category_var = 'business'
                    if call.data == 'entertainment':
                        category_var = 'entertainment'
                    if call.data == 'general':
                        category_var = 'general'
                    if call.data == 'health':
                        category_var = 'health'
                    if call.data == 'science':
                        category_var = 'science'
                    if call.data == 'technology':
                        category_var = 'technology'
                    if call.data == 'Default':
                        category_var = ''
            elif call.data == 'Country_settings':
                country_markup = types.InlineKeyboardMarkup(row_width=2)
                country_markup.add(types.InlineKeyboardButton('Китай', callback_data='ch'),
                                    types.InlineKeyboardButton('США', callback_data='us'),
                                    types.InlineKeyboardButton('Россия', callback_data='ru'),
                                    types.InlineKeyboardButton('Польша', callback_data='pl'),
                                   types.InlineKeyboardButton('Украина', callback_data='ua'),
                                   types.InlineKeyboardButton('Германия', callback_data='de')
                                    )
                bot.send_message(call.message.chat.id, text='*Новости из какой страны вы хотите читать?*',
                                 reply_markup=country_markup, parse_mode="Markdown")

                @bot.callback_query_handler(func=lambda call: True)
                def country_handler(call):
                    global country_var
                    if call.data == 'ru':
                        country_var = 'ru'
                    elif call.data == 'us':
                        country_var = 'us'
                    elif call.data == 'de':
                        country_var = 'de'
                    elif call.data == 'ua':
                        country_var = 'ua'
                    elif call.data == 'ch':
                        country_var = 'ch'
                    elif call.data == 'pl':
                        country_var = 'pl'
    elif call.data=='CheckNews':
        global category_var
        global language_var
        global country_var
        titles = []
        descriptions = []
        if category_var!='' and country_var!='':
            top_headlines = newsapi.get_top_headlines(category=category_var,language=language_var,country=country_var)
            for article in top_headlines['articles']:
                titles.append(article['title'])
                descriptions.append(article['description'])

        elif category_var!='' and country_var=='':
            top_headlines = newsapi.get_top_headlines(category=category_var, language=language_var)
            for article in top_headlines['articles']:
                titles.append(article['title'])
                descriptions.append(article['description'])

        elif category_var=='' and country_var!='':
            top_headlines = newsapi.get_top_headlines(language=language_var,country=country_var)
            for article in top_headlines['articles']:
                titles.append(article['title'])
                descriptions.append(article['description'])

        elif category_var=='' and country_var=='':
            top_headlines = newsapi.get_top_headlines(language=language_var)
            for article in top_headlines['articles']:
                titles.append(article['title'])
                descriptions.append(article['description'])

        for i in range (len(titles)):
            try:
                bot.send_message(call.message.chat.id, text='*'+titles[i]+'*\n'+'\n'+descriptions[i],parse_mode="Markdown")
            except:
                pass
if __name__ == '__main__':
    bot.polling(none_stop=True)