The issue was fixed, adding a minus sign before the chat ID: before: https://api.telegram.org/bot123456789:AAQFb1byb3LEwMes_TQeCM1k5wsFb_VguhG/sendMessage\?chat_id=123456789&text=Hello after: https://api.telegram.org/bot123456789:AAQFb1byb3LEwMes_TQeCM1k5wsFb_VguhG/sendMessage\?chat_id=-1234567...