firestick will not reconnect with internet

unable to reconnect with firestick max, all other devices connect with no problems, including a fire tablet to tmobile internet. my firestick does connect via hotspot from cell. all was working fine until a week ago. i have unplugged and restarted all devices. still will not connect. keeps saying no internet. Amazon is sending out a new firestick after we also tried a factory reset. I've seen other post but really no explanation for a simple fix.