Too few replies to incoming private messages. Conversion is 0%

We have a bot that just sends the messages to the users who subscribed to this bot + this bot launches web app.

Messages that are sent to the users have such structure

{
    "chat_id":"1337",
    "text":"test message",
    "parse_mode":"HTML",
    "reply_markup":{
        "inline_keyboard":[
            [
                {
                    "text":"test button",
                    "url":"https://some.com"
                }
            ]
        ]
    },
    "disable_notification":false
}

And we've got this message from the bot:

Too few replies to incoming private messages. Conversion is 0%

And here (and anywhere) no descent description what does it mean and what we should do not to have such notification.

Your bot is not replying to all messages that are being sent to it (the request/response conversion rate for your bot was too low for at least two of the last three 5-minute periods).

To what messages the bot should reply? Messages that are sent like notifcations or messages that user can type for the bot/smth else?

And don't see anything related to this in the telegram-bot-api code.

Will we have any restrictions due to this message? What should we do to avoid such messages from the bot?

tdlib / telegram-bot-api

Too few replies to incoming private messages. Conversion is 0% #602