home control app disconnected from gateway

Hello,

I have an issue since a week or so with the home control app that disconnected my home and devices from the gateway. 
It happened without any change from my side after it used to work for almost a year. 
I’ve tried everything mentioned in this recommendation: https://www.perplexity.ai/search/0b11ef73-f8be-4ec3-99a4-6be75b49ba01#0

- the WiFi is set to use 2.4 ghz only
- rebooted the router
- the gateway is in the same room at the router and I have the latest livebox 7 from orange
- router security is set to both WPA2 and 3
- Mac filtering is disabled and router firmware is updated
- the WiFi channel is set to automatic and UPnP is active
- I reinstalled the home control app and rebooted my phone (tried also from another device)

Things that I did not try yet, but can’t see how it would help are:
- changing the WiFi password to avoid special characters (the same password was working for a long time)
- setting a static IP address to the gateway or using the Google DNS servers 
- resetting the gateway (I am afraid to reset it cause I had an issue in the past with a hard reset that delinked it from the rest of the devices in my home, including the main Prise control and I had to replace the gateway). 

Can you please help check this and let me know what are the steps I can try on my side next?

Home control version: 4.4.0 (362)
Mobile phone device: IPhone 16e (iOS 26 Developer Beta 4) / iPhone 16 (iOS 18.5). 
Device: https://www.legrand.fr/pro/catalogue/pack-de-demarrage-celiane-with-netatmo-avec-prise-control-et-commande-generale-departarrivee-blanc