Shelly devices seem to be offline in app

Hello,

I have some Shelly devices and they are working more or less stable and robust (~20-30 devices - most of them are Shelly1 and Shelly 2.5 devices) I use them via Home Assistant integration and via manual input.

I haven't checked the Shelly app for months.

Today I opened and noticed that I can reach via the app the devices which are connected to cloud. All the devices on which the cloud is disabled are marked as offline in the Shelly App, but it's not the case, since I can reach them via web interface and also via Home Assistant.

Do you have any idea what could cause this and how should I get the local-only devices working again in the Shelly app?

I tried to delete one device in the app, after that the app could find and add again to my account. Then I disabled cloud connection and the device disappeared from Shelly.

The network is quite stable in my opinion, 2 Unifi AP behind a Mikrotik router, Home Assistant is hosted on a Synology NAS in Docker. The Shelly devices are set to fix IP.