I have just experienced the same issue on an NDC-5.
I have successfully logged onto the web server in the past, initially to configure the unit, and then once a few months later to reconfigure the unit after i noticed the status LED was red, but otherwise the unit has functioned as intended.
Yesterday I noticed some of my NMEA0183 devices not doing what they should be doing, and i found the status LED on the unit red again, but this time i was not able to connect to the web server to inspect and rectify. I basically lost the whole day today trying to resolve, going mad thinking it was my network configuration on the laptops. 3 different laptops with various web browsers resulted in the same blue screen (of death?) pointing ‘Keil Embedded Development Tools’.
Was there a resolution to the original query from 6 months ago that can be shared?