@Sinahadayati This could be due to a cable issue, switch port issue or AX10 LAN port issue. So you could experiment by changing the AX10 LAN port or switch port where you plug the cable or the cable...

@Ramakrish85 This router model is an ISP provided device and that's the reason you can't find a firmware on the support portal. Usually the ISP that provided the device could help with that.

@Goblino Try resetting the router (hold the reset button for about 10 seconds). If ther's no improvement and the device is under warranty contact your retailer or your local support.

@alexkn Follow this troubleshooting guide on what you should do if you can't access the internet.

@Stuart_R You can connect RE330 as a second range extender to your main router to further extend its wireless coverage if you want.

@Paul99 If your idea is to have the same wireless SSID on your range extender like on your broadband hub you can use for example RE315: Copy host SSID button will make the SSID of teh extended...