WAC124 AP/router - cannot login

We have two WAC124s, both configured as access points and connected via ethernet to the router.

These were straightforward to configure when we bought them and have worked well. However I recently tried to log into them and cannot access either of them. Trying to log in when they are connected to the internet takes you to the Netgear page - entering the login details results in some 'thinking' before the login page is just redisplayed. As an aside, why one has to connect to a server hundreds or thousands of miles away to access a device just a few feet away is beyond me.
Disconnecting the devices from the internet and connecting directly, as described in the user manual, just results in a failure to connect. I do not believe that both devices suddenly developed the exact same problem so I'm baffled.

I'd be most grateful for any suggestions. Thanks.