GXP2170 web interface not working


The web interface on my two brand new GXP2170 phones doesn’t work. When I try to login, with admin/admin, as soon as I hit logon the text boxes for username and password turn grey, indicating it responded to pressing the logon button, but nothing more happens. I’ve used multiple browsers on multiple computers, with two different GXP2170 devices. Same results.
On one of them I was able to get the firmware updated via the menu system and Grandstream’s firmware website, but that didn’t fix it either.
Any ideas what could be wrong - or is it a bug?