For your information, I created extra signal of 2.4GHz using KPN Box 12 web ui. But still no use. I also updated the box 12 to latest version V12.C.23.15.06

Attaching the screenshot of the error on TV

@Adityaa 

Tried with both n and g, but no luck. For your information it was working fine yesterday in ax mode.

@Adityaa If 802.11n can't help, maybe the WPA setting in WPA2 only. Btw you can't create a 2.4ghz only main wlan, but in the tab "extra wifinetwerk” is possible to create a extra 2.4Ghz only wlan . You can check in "connected devices” wich devices are connected to 5.0Ghz wlan. All speeds above 433Mbs are 5.0Ghz

Hi @TDN , Yes you are right. WPA setting is in WPA2 only by default. You want me to try extra 2.4Ghz wifi with other options below?

Yes I am aware how to check connected devices. I dont see any issues with the devices using 5Ghz signal, but the issue is with the devices which only can connect to 2.4 GHz signal.

After waiting around 6 hrs the issue got fixed by itself and in the below image you can see the devices connected and configuration of 2.4Ghz signal

For now it got fixed, but I am pretty sure it will disconnect again soon.

So all I see is something is wrong with 2.4Ghz signal, which we have to find and fix.

@Adityaa Not possible in main wifi but in extra wifi

@TDN Which Beveiliging option you want me to try? For now my devices are connected, so I can try when they disconnect.

@Adityaa WPA3 is the new encryption of wifi6, it is not fully compatible with wpa2. If you use mixed mode wpa2/wpa3 old devices may cannot connect to wifi.

Right now I am using only WPA2-Personal, which is also not working.

Look at the moment that you can't connect to wifi, how many devices are online and connected with 2.4Ghz. Because wifi5 allows maximum 4 devices to connect simultaneously. You can extend the limit to use a extra access point. Give your devices with connecting issue a static IP adres via DHCP revervation en lower the DHCP lease time. Let another 5Ghz capable devices connect to 5Ghz band (wifi6)

I have only 2 devices at home that are operating on 2.4GHz. When the issue occurs, none of the 2 devices at home are able to connect to 2.4GHz. So I believe it has nothing to do with wifi5 or wifi6 profiles. For now I reserved static IP address for both the devices using 2.4GHz as shown below. Lets see if it works

@Adityaa Wifi6 allows communication to 8 devices at same time while wifi5 allows only 4. The 2.4Ghz devices are surely wifi5. If you create a wlan 5.0Ghz with seperate SSID en let 5.0Ghz capabel devices connect to this wlan you can avoid the issue with connection limit. Otherwise you can buy a superwif2 from mykpn to extend your wifi range en connection limit.

Hi TDN, as you can see in this image all the devices are connected now without any issue. So I don't think this is a issue related to connection limit. I even connected other device now and the total devices connected right now is 7 and I see no issue with connections. I remember connecting more than 10 devices at same time for this wifi. Also as I mentioned earlier, when the issue occurs, no devices are connected to 2.4GHz. Do you still thinks its a connection limit issue?

Hi @Adityaa! I'm happy to read that you’ve already received a lot of help from @TDN. Too bad the problem isn't solved yet, so I'll think along as well. 

It's just the 2,4 Ghz network that's giving problems along with your Philips TV and DELL laptop that lose connection, despite all the tips. 
The 5 Ghz is stable and the other devices in your home aren't losing connection there? 

Is it possible for you to connect only the DELL laptop to the 2,4 Ghz network? See if it stays stable then, and only then add the Philips TV. I want to see whether any of the devices are causing the disruption in the network maybe. 
If it also fails with the DELL laptop, then try connecting only the Philips TV. How does that go?

Hi @Sanne van KPN, yes you are right, the devices connected to 5GHz signal are working fine and they don’t ave any issues. The issue is with devices which can only connect to 2.4GHz but not with 5GHz. When the issue exist none of the devices connect to 2.4Ghz network. I did tried TV alone and Dell laptop alone, none of them connect no matter what I do, untill the issue fixes by itself. I was using kpn since a year and everything was fine until last 5 months. And suddenly this issue started 5 months ago which used to happen rarely, but now a days its happening too often. Right now its connected so I can’t troubleshoot. I will post here immediately when I lose connection then maybe we can start troubleshooting

Got it, thanks for elaborating @Adityaa! I'm not always at work and sometimes I might see messages late, so troubleshooting while the connection is gone can best be done through calling us on 0800-0402. 
I hope my colleague will be able to see something while the disconnect is happening. Will you let me know how it worked out? 

Hi @Sanne van KPN , calling KPN is the first thing I did when I am not able to connect. After few tries of troubleshooting they mentioned that they cant do anything morethan that and asked me to post it in this forum

Unfortunately I don't have many more options than my colleagues on the phone do, the main difference is that you can connect to us on the phone quicker. So it's useful for when your services aren't working at one specific moment, then my colleague can test the connection right away and hopefully the system will then see and solve the issue. 

However, if you’ve already called with us while you were experiencing this issue and my colleague didn't see anything, then that's not the solution either.

If I look at the pictures you sent before then it looks like you’re using the Extra Wifi option in the Box 12. What if you stop the Extra Wifi and create it again? Just to see whether that one does stay connected to the DELL and Philips. 

The extra wifi was created to test if that works. It didnt and I tuned it off. Right now my TV is unable to connect and I reset my TV to factory setting but still its unable to connect. 
I dont see any other way than switching the network to fix this issue. I was using Ziggo earlier with same devices and never faced this issue. To be frank I dont have issues with KPN for almost 10 months and it started suddenly now

I suspect it has something to do with the new software on the Box 12. We’ve seen a few more customers experience this issue, but there isn't a fix yet. So a few options remain: 

• Wait for a new update on the Box 12 that fixes this. Once a release date for an update is known we'll post about it in our Product Updates, so keep an eye on the posts there or subscribe to receive notifications about updates
• The other option is to buy a SuperWifi point and connect the 2,4 Ghz devides to that one. That tends to solve it most of the time and if it doesn't, you'll be able to return it within 14 days. A different wifi repeater from another brand is an option too of course

So for the KPN’s mistake of malfunction update, you are asking me to spend money on purchasing SuperWifi. Why cant you(KPN) provide me SuperWifi and I will return the same once the issue is fixed in the new update?

That's why I said different repeaters are also an option. You’re definitely not obligated to buy a SuperWifi from us. 
Unfortunately I can't provide one for free. If buying a repeater doesn't have your preference then it's waiting for an update to fix it. 

@Sanne van KPN may I know what are these profiles marked in Red? Does applying any specific one will help in fixing the issue?

That either sets all your wifi networks to Wifi-5 or Wifi-6. Some older devices will have difficulty connecting to Wifi-6, so you could set it to Wifi-5 to see if that helps. 
You can do this by clicking ‘Toepassen’ behind Wifi-5. If that doesn't help you can always turn it back to Wifi-6.

HI @Sanne van KPN , thanks for the reply. But right now I see none of the profiles (wifi5 and wifi6) are active. Is that normal?