404: Not Found after restart

Configuration
1

Hi,
Very new to HA (<24 hours old). Spending a lot of time to figure out the most basic things. My HA running on RPI 4 is connected with an Ethernet cable to Google WiFi access point, which itself is connected to the modem with an Ethernet cable. HA was up and running but after I restarted it using the HA app on iPhone, I am getting the 404: Not Found error. I also powered down the RPI and restarted it, yet I get the same error.
I uninstalled the iphone app and reinstalled it to see if its an issue with dynamic IP, the app can’t find an HA installation.

Please help!

2

I could say ssh in and look at the logs but if you’re that new just start over again.

3

Thanks Tom. I prefer to see why this happened so that I can learn not to repeat the same mistake once I get deeper into HA.
I am trying to SSH but I am unable to connect. I am getting an error. Network error: Connection refused.

I didn’t follow step #4 from this guide: https://www.home-assistant.io/getting-started/ Is configuring for static IP address recommended? Does RPI’s IP address change dynaically by default?

4

Yes definitely. That or reserve an address for it in your DHCP server.