To clarify, to me the OBi Dashboard is the one that I get to via
obitalk.com when I click on "My Dashboard" and I have trouble logging into the device webpage which I get to using the device's IP address on my LAN.
When I tried again today, the default password was working again on the device webpage. Because I don't want an easily guessable password on a device on my LAN, I tried again to change it using the OBi Dashboard. I changed it by going to the dashboard, clicking the device, entering a new password in the field "Webpage Admin Password", and clicking "save". The device webpage appeared to not respond at all briefly, then attempts to use the new password failed and also the old password failed. Since the old password no longer works, I assume it has changed, but perhaps it is in some long transition state? The password I tried is only 8 characters alphanumeric, so I don't think there's any issue with it being long or having unexpected characters.