Sorry for delay.
The support team told me that the Landroid gets disconnected from Amazon server. I guess they have to implement a retry connection mechanism, it has nothing to do with the WiFi signal range. At least in my case the garage has full WiFi signal and over night the Landroid gets disconnected and I have no communication with it in the next morning. They flashed a new patch today and I have to provide them the log file.
This issue I guess it is common on all 2019 Landroids, are there other persons who observed it ?