@sanikbug2k18 What is your device exactly, give here the model and the HW version ? On the bottom of the device there's a sticker with these details.

@sanikbug2k18 If the device is under warranty you can contact the retailer for a replacement. If he can't help, then you should contact your local support to be advised further.

Are you holding the reset button at least 10 sec ? What's the device led status during the reset procedure ?

@Dkhoo As I expected. You can mark your thread as resolved by marking a post as a recommended solution.

@Toople Using Google SMTP doesn't require any port-forwarding on your router - just setting SMTP server address and credentials (username/password). If you see these ports in UPnP then the router...

@sanikbug2k18 Execute a hard reset`- method 1.