@Gumbofizz Did you try to set the entire port range in the Internal Port field ( 7777-7791 ) ? If you receive a similar error in this case too, then most probably its FW release doesn't support...

@BDMcG If you use a DSL broadband service and your broadband supplied router is a DSL modem, then you'd need the device. If your broadband supplied router is just a wireless router then you won't...

@Mirza_Baig After factory reset you should re-configure the router from scratch - here's a video setup guide.

@tontze Yes, you can control the guest access here:

@NazmulHossain No, you can't use AX1500 as a wireless extender - AX1500 supports AP mode for which you'll have to use an ethernet cable.

@Anandk In case you forgot the router management password, you have to reset the router to its factory defaults pressing the reset button for 10 seconds, then re-configre the router.