Your phone is likely at carrier server lock, if it was originally a carrier locked device, you could manually flash the latest android version via ODIN flash, or you could flash to the fully unlocked XAA device by flashing xaa or fully unlocked OS equivalent of your model number, you could get the latest OS files from samFW. You'll start getting updates normally.
Or simply if you want the simpler solution, just plug your phone in a PC, use Samsung smart app to manually get the update from Samsungs servers.
