You can have a situation where TataPhoton max device can show green light instead of usual blue light and it can happen due to your exceeding your high speed quota which in unlimited case is 5 GB. Just note than 1 GB has 1024 MB.
Now green light shows that your device has stopped working and now you ned to change from the settings to Tata Photon Wiz by using the drop down menu as given in profile name. Just save and now your device will start working at slow speed. As and when your billing cycle gets over and you are in a new billing cycle you have to rechange to present settings for a photon max device as shown in screenshot below.