Hi @grbit, welcome to our forum!

I'm not sure what would cause this, are you using any other wifi repeaters or routers on your network?

Hi @Thomas !
I use only the router that I got from KPN, nothing else.

Ah that narrows things down a bit, which modem do you have?
I'm thinking this could be an issue where your devices don't work properly with either 5Ghz WiFi or Wifi6 if you're using a box 12.

In our knowledge base you can find the steps for each modem to add a guest network which you can set to 2,4Ghz only.

To turn off wifi6 on the box 12 you can follow these steps:

RBxx schreef:

Hallo ​​​​​,

De KPN Box staat standaard op WiFi 6 (802.11ax). Dit is de nieuwste versie van WiFi.

Oudere Intel-chips kunnen hier niet/slecht mee omgaan. Mogelijk heeft jouw laptop daar last van.

Zet daarom in de Box 12 de Wireless Mode op 802.11b+g+n (2.4GHz)  en 802.11a+n+ac (5GHz).

Inloggen gaat via https://mijnmodem.kpn met het admin password op het etiket achterop het modem. Kijk voor meer info over de KPN Box 12 in de Online handleiding KPN Box 12

De andere oplossing voor dit probleem is mogelijk de driver van je laptop handmatig te updaten via de Intel website.

 

Thank you for your reply Thomas. Indeed, I use box 12.

But I think you are missing something. I have had my devices working for a few months. Two of them support WiFi 6 and all of them support 5Ghz bands. So it doesn't look like it's a problem with the WiFi standard, and it worked for a long time before.

Nevertheless, I tried setting up a separate 2.4Ghz only network, and then a separate 5Ghz only network. In both cases, all the phones just disconnected as before.

Do they work on other wifi networks? Or not?

@PeterG Yes they do. I was able to share WiFi from one phone to another.

Can you picture three phones all losing WiFi connection at once? It's about as probable as winning the lottery two times consecutively, I reckon

I have no clue what could cause this, you could try forgetting the network on your phones and adding them again.
If that doesn't do it you could also give your box12 a factory reset or even the phones but I doubt that'll be necessary 

I found the problem. Sorry for bothering you, I was shooting my own leg here.

So, the reasons was that I’ve set up local DNS server to cut some ad from home. All computers were able to use other DNS servers as a fallback, while phone were only relying on the one that is provided by the router.

Now I add secondary DNS server in case I have maintenance or server is down for any other reason, and it works fine.

Thank you all for your time!

Ohh! no worries Thanks for the feedback!