From BioStar 2.5.0, you can configure an Email about the device disconnection detected. When a device is disconnected, the email will be sent to a recipient you set.

Go to Setting > Trigger & Action.

Select the certain device. Then, check the box named Device Disconnection Detected and Biostar.

Click to configure the email server information. Then, type the information on your email server.

When it comes to setting of SMTP Option, refer to the below screenshot.
Set up your SMTP. If you are unsure what the settings are, please follow this article → How to configure SMTP and Test the recipient address.

Add a Recipient and click Apply button.

When the device is disconnected, an email titled “[BioStar Alert] Device Disconnection Detected” will be set to the recipient you add.