I just did a factory reset of my modem as I has the same issue with not being able to log in.
I did the same thing at my sisters and for her the default password was __NOT__ "password" but the default wifi pass phrase printed on the button of her modem. For me however this is __NOT__the case. I'm locked out of my modem after trying the passphrase, "password", my old passphrase I'm stuck
SOLVED: So for my case where the web portal always reported incorrect password for admin! even after I did a reset (pushed reset button for 10s) I was able to solve it by actually holding down for 10s 🙂
I counted out 10s then let go last time. I saw the modem reset and sure enough my wifi settings were reset however still no luck on the password. This time I just kept holding it down; I did not release the reset button until I saw the LED on the modem turn orange. After that when i re-connected to the default wifi and opened http://10.0.0.1 I was now treated to a first time setup screen instead of a login screen. I followed the steps (setting my wifi ssid and pass phrase) then after it switched over to my named ssid when I reconnected I got the standard admin portal and this time the default credentials worked as advertised (admin:password) :woohoo:
I think holding the reset for 10s then releasing is a reset but holding the bugger down until the modem cries uncle is a full factory reset and that fixed my issue :+1: