my galaxy m31 switch off automatically. What is the reason?

[Samsung_Support3]

Dear Samsung Member,

Greetings from Samsung Customer Support!

To resolve auto restart issue please follow below given steps:

Go to Settings > General management > Reset > Turn off auto start.

For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).

Thank you for writing to Samsung.

Warm Regards,
Samsung Customer Support

[Ron12]

My Galaxy M31 is getting switch off frequently. Why it happens and how to avoid this ?