Unable to log in via web UI on certain computers

I run Nextcloud as a Docker container on an Unraid system. Outside of home LAN access is via an nginx reverse proxy.

My new desktop computer (Ryzen 3800x, 16GB RAM, GTX 1070) does not show the username and password boxes when I navigate to the login page for Nextcloud in Chrome or Edge. This happens when I try to access it using the local network address or via the external web address.

It works fine when I navigate to it from my laptop or external work computer though.

Does anybody have any ideas as to why this might be happening?