I think ONT in bridge mode not in RG mode.. so you can't log into the ONT.
Still you require any details and support. please let me know your telephone number to find the ONT mode.
I have 3 lights glowing on the ONT. Power ,Fiber and Data. I've kept auto IP (DHCP) and Auto DNS set in IPV4 settings on my desktop as advised for configuring BSNL ONT (BSNL FTTH Modem settings | Fiber router configuration). I'm still getting page not reachable prompt when trying to access 192.168.1.251. My ONT is Alphion AONT 100C. Could someone please advise. Much Appreciated.