Cannot perform update to version 2.1.4.14 of firmware for Orbi RBR50 router + satellite

I have a NetGear Orbi RBR50 router + satellite (bought last year, 2017). My computer is running version 2.1.4.10 of the firmware for the set (router + satellite) ― in a Mozilla Firefox Quantum version 62.0.2 (64-bit) browser (on a Windows 10 computer).

I have for some time been trying to upgrade to version 2.1.4.14 of the firmware ― but have found myself unable to install it for the following reason:

When I open the http://www.routerlogin.net/index.htm and click the “Advanced\Administration\Firmware update” tab, the message “Please wait a moment” appears (in Danish, atop a blank page) ― and then, nothing happens.

I have repeated this process many times, and waited for hours for the “Update” page to appear, but always remain stuck with the “Please wait” message. What should I do?

Kind regards, Nikolaj Lunøe, Copenhagen, Denmark, nikolaj@capability.dk