En route to US on a B777 right now and the login page tkwifi.net was acting up, on the laptop, clicking on green button was not doing anything, but on the phone it was working fine. The solution was to visit the tkwifi.net site in an incognito window.

On a separate note, Android by default uses randomized device MAC address, causing problems with captive portal based hotspots. After fixing the portal page issue, I was told I already used two devices and have to log off from the phone.