After numerous failed troubleshooting attempts and help from Plethra support, I was able to resolve the issue by assigning a link-local address on the R Pi server.
Below are the steps I used to assign a link-local address. Note: I'm using the ethernet port and thus the network device is eth0 in my case for step 4 below. If your using WIFI, your network device maybe different such as wlan0. Use the command "ifconfig" to query your device as indicated in step 3. Look for the interface which has the current R Pi IP address (usually in the form of 192.168.X.X.)
- Bring up a terminal window on the R Pi server (you can also SSH into the R Pi server from another machine):
Click R-Pi Application menu (top left icon) -> Accessories -> Terminal
- Install the avahi-autoipd package:
sudo apt-get update
sudo apt-get install avahi-autoipd
- Query the current network device in use:
- Edit rc.local script file to insert the proper command to run at after every boot:
sudo nano /etc/rc.local
- Insert the following command above the line "exit 0":
sudo /usr/sbin/avahi-autoipd --force-bind eth0 &
- Save the changes to rc.local and exit:
Once the R-Pi server boots up, run the "ifconfig" command again. There should be a new device with a link-local address (169.254.X.X). The device name should be similar to eth0:avahi or wlan0:avahi.
From the Audio|Acacia interface, I can now drag any AE device into any room/listening session.