Most likely the broadcast from the TV station stopped or was switched to DVB-T2
If you only use the antenna and the TV, you received analogue signals. Eventually the broadcast cancaled this and switched to digital signals which you can only get by using a set top box or a HDTV with such an integrated receiver.
If the antenna is powered make sure it's plugged into a working AC outlet. If it has a wall wart power supply those can go bad.
Make sure the antenna is screwed firmly to the TV antenna jack.
You can try rescanning for channels to see you can bring them back.