1) Click on add new monitor.
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2) Now click on setup Notification
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3) Select notification type telegram and using bot token and chat ID complete the notification details as per requirement.
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You can get your chat ID by sending a message to the bot and going to this URL to view the chat_id:
https://api.telegram.org/bot%3CYOUR%20BOT%20TOKEN%20HERE%3E/getUpdates
4) After this just Test and Save it.
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5)Now you will get the notification in Telegram like this.
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i. The red symbol shows the site is down.
ii. The green symbol shows the site is now running active.