Adding debugging page

content/debugging-failures/_index.md

@@ -27,7 +27,7 @@ DefaultRuntime - Initializing Pi4J context/runtime...
 DefaultRuntime - Pi4J context/runtime successfully initialized.
 ```
 
-### Error GLIBC_2.33 not found
+### Error `GLIBC_2.33 not found`
 
 When the error `GLIBC_2.33 not found` is shown in the startup log, you need to update the Operating System as the required dependencies are not available to communicate with the GPIOs.
 
@@ -38,6 +38,20 @@ java.lang.UnsatisfiedLinkError: /tmp/libgpiod14998985341386605622.so: /lib/aarch
 Exception in thread "main" java.lang.UnsatisfiedLinkError: Pi4J was unable to extract and load the native library [/lib/aarch64/pi4j-gpiod/libgpiod.so] from the embedded resources inside this JAR [/home/pi/maven/pi4j-example-minimal/target/distribution/./pi4j-library-gpiod-2.7.0.jar]. to a temporary location on this system.  You can alternatively define the 'pi4j.library.path' system property to override this behavior and specify the library path. 
 ```
 
+### Error `pigpio initialisation failed`
+
+For some Pi4J functionality, `root` privileges are required. If you get an error like this, you need to execute your application with `sudo`:
+
+```shell
+[main] INFO com.pi4j.util.Console -
+[main] WARN com.pi4j.library.pigpio.impl.PiGpioNativeImpl - PIGPIO ERROR: PI_INIT_FAILED; pigpio initialisation failed
+Exception in thread "main" java.lang.reflect.UndeclaredThrowableException
+...
+Caused by: java.lang.reflect.InvocationTargetException
+...
+Caused by: com.pi4j.library.pigpio.PiGpioException: PIGPIO ERROR: PI_INIT_FAILED; pigpio initialisation failed
+```
+
 ## Unexpected Results on Electronic Components
 
 If your software starts OK, and the log output shows that everything works as expected, but you still don't get the desired result on the connected electronic component, check: