Most likely I understood what was the matter.
Kestrel has launched a new site for shooters.
https://kestrelballistics.com/
And the direction for other purposes and with other devices was left on the old website
https://kestrelinstruments.com/
I've downloaded another Kestrel Link app. When the application is launched, it does not connect to the server and writes that there is no Internet connection. Internet connection is solid 500 mb/s
I connected the app via Bluetooth with my Kestrel and tried to update the firmware from the application, but it failed again.
an error popped up about the lack of an Internet connection.
I turn on the VPN on my laptop and everything works. But I can’t enable vpn on my cell phone, and I can’t update the firmware of the device.
most likely New hosting does not allow IP requests from Russia. Therefore, neither updating the firmware nor simply visiting the site works. you need to write to them to fix this problem.