Looking for some guidance. Everything was up and running. Stable for more than a year. Yesterday I fooled around with a template sensor for the first time. Modified my yaml file, and created a new file, sensors. All was working fine. Sensor worked. Tried to integrate it into an entiity card but couldn’t get it to work, and gave up.
This morning I cannot access home assistant via duckdns. I no longer see it on my network. Rasberry pi has power, red light on, but no lights on for the ethernet port. Tried different cable and port. No difference.
Did my Pi coincidently go bad? any help, or troubleshooting would be most appreciated.
I know, it’s a stressful situation, but please take a deep breath. As many people are here to help, you’re not giving us any useful information about your setup, the used hardware, what exactly you have done to solve the problem (like a reboot) - anything to help you.
Keep calm, and if you have a recent backup (what you should have), this can be solved!
First thing I would try is find a good power supply with enough power, and try with that. You would not be the first to have problems with insufficient power supply.
Edit: as you also do not see any lights on the ethernet port, try a different ethernet cable.
There’s a step in the Pi setup instructions for SSDs where you ensure the Pi is flashed properly to boot SSDs (it’s been a while since I’ve done it…) as long as new pi has that… It should just go.
You could also pull all the stuff off old Pi and try to boot it with an SD just as an additional proof of pi failure.
And as soon as it’s up make a full backup and save it somewhere else.
As many people are here to help, you’re not giving us any useful information about your setup, the used hardware, what exactly you have done to solve the problem (like a reboot) - anything to help you. 
