Lost master local connection 'Failed to connect'

[Disincentivato]

Hi,
from yesterday my master unit is not reachable from the local network.
I can see all the data from the app and no error on the display, I also can ping the unit.
I tried delete the unit and it doesn't connect anymore, I get 'failed to connect ' error.
I reinstalled the integration, restarted the modem and restarted HA. I haven't solved it yet.
The secondary unit is connected.
Is there anything I can check to fix this?
thanks a lot for the support.