Sounds like there is a setting that needs to be adjusted on your router to allow crosstalk between the two frequencies. 

Both the Beam and the Sonos One are 5Ghz capable, but there is a potential price to pay, as 5Ghz doesn’t penetrate walls as much, or go as far as 2.4Ghz…and if your Sonos Ones are set up as surrounds, then both the Beam and the Ones are already using a 5Ghz channel to communicate between each other. 

Not that it matters for your problem, but according to https://support.sonos.com/en-au/article/supported-wifi-modes-and-security-standards-for-sonos-products no Sonos soundbar is 5Ghz capable, probably because it is reserving the 5Ghz capability for the dedicated surround link.

Hi @Eido Lu,
Yes, as @106rallye mentions, all Sonos HT master products connect to the network using their 2.4Ghz adapter and their surrounds/Sub use a 5Ghz ad hoc wireless connection between themselves and the HT device.

This issue is probably related to the router not passing the SSDP multicast ‘device discovery’ packets between its two different wireless segments. It can usually be solved by changing a setting in the router (depends on the make/model of router), or often another workaround that ‘may’ work, is to wire one Sonos product to the router (not a HT surround or Sub). That causes all Sonos products to then use SonosNet ‘wired mode’ instead.. note it may take upto 10 minutes for all devices to switch to their SonosNet internal connection and if any fail, then simply reboot (power-cycle) the device. Then just see if the Sonos mobile controller finds all the devices… it’s often a good way to go about resolving these type of issues, until the router issue/settings can be resolved.

Hope that suggestion works for you.

If following the suggestions given thus far of changing a setting in your router sounds a bit complicated here a possible quick fix. This assumes you haven’t done something to your router or introduced an extender/access point on your network.

Unplug your Sonos and then reboot your router. It may have received and update but requires a re-boot to complete the process. After the reboot power cycle your device and plug in your Sonos. The process may take a few minutes so be patient.

Sometimes a router reboot is all that’s required.

Hi @Ken_Griffiths,

thanks for your clear explanation. I couldn’t find any settings in my router (Asus RT-AX86U) about passing packets between two frequency segments. I am not sure what’s the setting in my router. But my other smart devices (e.g. Tuya Smart Curtain) connecting to 2.4GHz wifi can be found and controlled from 5GHz wifi without issue.

Next step, I plan to connect with cable and see how.

@Eido Lu,
I seem to recall with that router IIRC, that users used to disable ‘QoS’ and/or ‘Airtime Fairness’ on that ASUS model to get it to work with Sonos, but maybe whilst in the configuration settings aswell, also check that the WiFi bands are not isolated from the wired LAN - usually that’s just a check box on most routers.
Hope that assists too.

ASUS routers often cause problems with Sonos because their defaults are, frankly, stupid. Search the forum for details of work-arounds.

Hmm…l’ve used Asus routers for years. In fact I have an Asus AiMesh consisting of three (3) Asus routers; all of which could be used as a standalone router. I have “QoS” enabled and “Airtime Fairness” “disabled”. The latter; as I recall, is the recommended setting for the majority of routers involving Sonos.

Connect my Bean with a cable solves all my problems.

still not managed to achieve it with wifi connection only. Since I just nice have a switch beside my Bean, connecting with a wire is acceptable. Thanks everyone’s help