Adds initial documentation for virtual bridge error

Author: levihackerman-102

content/en/community/hackathons/sessions/baby-steps/content/Demos_02.-Building-and-Running-the-httpreply-Application.md

@@ -99,6 +99,13 @@ oOo oOO| | | | |   (| | | (_) |  _) :_
 Listening on port 8123...
 ```
 
+In this step you may face an error : 
+```
+access denied by acl file
+qemu-system-ppc64: -netdev bridge,br=virbr0,id=net0: bridge helper failed
+```
+For resolving this, check if `/etc/qemu/bridge.conf` exists and if it does add the line `allow virbr0` to it to allow your bridge to run.
+
 The boot message confirms the assigning of the `172.44.0.2/24` IP address to the virtual machine.
 It's listening on port 8123 for HTTP connections on that IP address.
 We use `wget` to validate it's working properly and we are able to get the `index.html` file: