Bitcoin Full Node Raspberry Pi 4 - lost access to umbrel.local

I installed a full node a few days ago using a Raspberry Pi 4. Today, with 75% synchronization of the blockchain, the device including the connected 1 TB hard drive fell off the table. Since then I no longer have access to umbrel.local. The device is also no longer warm/hot, so it appears to be “dead”. “The connection to the server www.umbrel.local failed”. The process may have been stopped by the shock. Has anyone had any experience with this? Is the device broken (circuit board?) or should I restart the installation process (Micro SD, Balena Etcher etc.)?

Thanks for your input!

There´s no www in address.
What about the lights of RaspPi and of SSD controller?

Force restart (power off) then plug a monitor to the hdmi output, power on and look for the error messages and if it gets an IP. Then just type IP in browser to access Umbrel.