@EliWeizman Something's wrong here - there's no LAN4 port as part of the default interface group. Are you sure that both your VR600 are in DSL Modem Router Mode (or at least the one you're setting in...

@EliWeizman In case of AP mode the second VR600 LAN IP address is in the same network subnet as your main VR600. So the main VR600 doesn't do any routing to reach a device connected to the second...

@EliWeizman " my friend have the VR600 V3 version(he saw the same issue) and he told me move the DHCP server from the VR600 to solve the issue but i want the management capability that the VR600...

@Mughalmughal If it's about router administrative password you can't recover. You should reset the device to its factory settings and reconfigure from scrtatch.

@azzido Make sure the device is in wireless router mode. On Advanced tab you should have a Security => Access Control option which will allow you to configure whitelist of MAC addresses.

@azzoug RE600X or RE605X are a good candidates too since they are rated AX1800 just as your VX1800v.