I am trying to develop simple telegram bot. When just started, I used polling to test the bot. When I tried to do something wrong, bot crashed with error message in console:
>> bot.send_message(1, '')

A request to the Telegram API was unsuccessful. Error code: 400. Description: Bad Request: message text is empty

(I should say, bot.send_message(1, ”) is wrong, message can’t be empty)
But when I switched to flask, I noticed, that bot no longer prints any errors, moreover, it just passes exceptions as if try: ... except: pass, or sometimes just try: ... except: return. Bot works, tho.

I tried everything. Tried to switch back to polling not touching any other code, and indeed, I got my errors back. If I put

try: 
    ... 
except Exception as e: 
    print(e)

over wrong function, it does report me an error.
Also it reports an error if I called function:

@bot.message_handler(content_types=['text'])
def on_text(message):
    print('s')
    bot.send_message(1, '')

this WON’T report an error on my message, even though it will print “1”.
But

@bot.message_handler(content_types=['text'])
def on_text(message):
    bot.send_message(1, '')
on_text

WILL report an error.
Why? How do i fix it? I can’t even imagine why is that.

Full test bot code:

from telebot import telebot, types
import flask


bot = telebot.TeleBot(token)
app = flask.Flask(__name__)


if bot.get_webhook_info().url != hookurl:
    bot.remove_webhook()
    bot.set_webhook(hookurl)


@app.route('/tovc', methods=['POST'])
def tovc_webhook():
    if flask.request.headers.get('content-type') == 'application/json':
        json_string = flask.request.get_data().decode('utf-8')
        update = types.Update.de_json(json_string)
        bot.process_new_updates([update])
        return ''
    else:
        flask.abort(403)


@bot.message_handler(content_types=['text'])
def on_text(message):
    bot.send_message(1, '')


if __name__ == '__main__':
    app.run()