Usually this is the problem with the band steering, the two band having the same ssid.you need to deactivate it https://fizz.ca/en/faq/my-wi-fi-network-cutting-how-do-i-fix-it
The Fizz Wi-Fi app is available for free at various online stores (Apple Store and Google Play Store).
1. Log in at: 192.168.0.1 from the web browser of any device.
2. Log in using the following information:
Username: cusadminPassword: xxxxxxxx (Password you chose during initial setup) 3. Go to the next section to apply changes:
Wireless → General Settings → 5GHz → Band Steering (Disable)