What is a possible cause for the motion detection feature not sending an email alert?

The SMTP server that the IP camera uses to send the email may be filtering emails to prevent spam from being sent through the server.

The SMTP server that the IP camera uses to send the email may not be filtering emails to prevent spam from being sent through the server.

Sudden changes in light level or movement have accidentally triggered the motion detector, and the configuration needs to be modified.

The issue cannot be related to SMTP filtering, light levels, or movement.