Question: All devices in your home network successfully connect to the Keenetic router Wi-Fi network, but one device does not connect for some reason. What could this be, and how do I connect it to the router?
Answer: In rare cases, we see that some devices (usually already outdated) cannot connect to your Keenetic router via Wi-Fi. In this situation, you need to pay attention to whether you have enabled Fast transition (802.11r) in your home network settings. An older phone or laptop may not connect via Wi-Fi when 802.11r is enabled on the router. There could potentially be issues with client and access point compatibility. In this case, it depends on the implementation of the Wi-Fi driver on the mobile device. For example, we've seen this situation with Samsung GT-N7100/N8000 smartphones and laptops with an Intel 4965/3945 adapter.
Technically, this happens for the following reason: when enabling 'Fast transition (802.11r)', another type of Auth is added to the IE (Information Elements) list for beacons, and Probe/Assoc Response packets, which the client does not understands and refuses to connect, although the list contains the WPA2-PSK network protection algorithm.
In this case, the problem is not hardware but in the software (driver) on the client's side. Based on our statistics, at the moment, modern client devices have no problem connecting to Keenetic when 802.11r roaming is enabled. Such cases are usually observed on older devices that are no longer properly supported by their manufacturer.
Faced with this situation, we recommend that you first update your mobile device system to the latest version available, or on your laptop, update the Wi-Fi adapter driver by going to the chipset manufacturer's website. If this does not help, the update is not available, etc., disable 'Fast transition (802.11r)' and 'Radio Resource & BSS Transition Management (802.11k/v)' in the Keenetic settings and then reconnect the device to the router's Wi-Fi network.
If your home network is built on a single Keenetic router (supporting only the 2.4 GHz band), turning off seamless Wi-Fi roaming will not affect your wireless network. For stationary devices that are less advanced or only work in one band, the Wi-Fi roaming setting is not relevant.
But in general, we recommend not turning off the 'Fast transition (802.11r)' mechanism, as it is necessary to use seamless roaming in the Wi-Fi system and provides much more benefits when enabled. Almost all modern client devices work with it correctly or even better (e.g. Apple mobile devices).
On dual-band models, you can enable roaming on the 5 GHz band only. For example, this will avoid the problem of connecting one of the devices on the 2.4 GHz band.
Roaming only for the 5 GHz wireless network will not only avoid the problem of connecting one of the old devices, but it will also switch the device between an extender and the main router only in the 5 GHz band, and this is just relevant for relatively modern and mobile clients, i.e., where it is essential (Wi-Fi calls, etc.).
For more information, see this article: Why can't my home network device connect to Wi-Fi network?