Hi @Jagarm , sorry you lose your data in certain areas. Do you have data roaming turned on? When you are out of range of Fido towers, if your data roaming is turned on or ask first, then you will be able to roam on other carriers towers. Keep in mind to turn it off if you are near the border or travelling to another country that you do not want to accrue roaming charges. You are not charged in Canada for roaming.
Also if you have Fido selected manually you may not be able to access other towers. That's one thought that came to mind. You could also do a network reset to ensure that you are registered on the Fido network. You can do this by going to settings, system and system reset. Hope one of these suggestions works for you