404 error in the browser log #556 🚑

docs/WEB_UI_PORT_DEBUG.md

@@ -0,0 +1,12 @@
+# Debugging inaccessible UI
+
+When opening an issue please :
+
+1. Include a screenshot of what you see when accessing `HTTP://<your rpi IP>/20211` (or your custom port)
+1. [Follow steps 1, 2, 3, 4  on this page](https://github.com/jokob-sk/Pi.Alert/blob/main/docs/DEBUG_TIPS.md) 
+1. Execute the following in the container to see the processes and their ports and submit a screenshot of the result:
+   1. `sudo apt-get install lsof`
+   1. `sudo lsof -i`
+
+
+![lsof ports](/docs/img/WEB_UI_PORT_DEBUG/container_port.png)