Can you please describe your network setup (which router, WiFi Extender, devices) ?
Are they all running the latest firmware? Where are you seeing this "network not reliable" message? If possible, can you post a screenshot of this error?
Make sure that your Wi–Fi router's firmware is up to date. If you're using an AirPort base station or Time Capsule, follow these steps.
Make sure that all Wi–Fi devices you want to use support the settings this article recommends.
If possible, back up your Wi–Fi router's settings.
If necessary, refer to the product documentation or manufacturer's website.
Forget or remove the Wi-Fi settings for your network from any devices that connect to your Wi-Fi router. This will prevent the devices from attempting to connect to your network with the old configuration. You'll need to reconnect these devices to your network when you've finished applying the new settings.
Configure all Wi–Fi routers on the same network with the same settings. Otherwise, devices could have difficulty connecting to your network, or your network could become unreliable. On dual-band Wi–Fi routers, configure both bands to have the same settings unless otherwise noted below.
