After the machine was deployed, it’s overview appeared on the screen. Then I clicked on my Sandbox’s public IP address to change the assignment from dynamic to static, but this message pops up:
I originally installed Sandbox version 2.5, but it gave me many problems so I decided to remove it. I also ended up deleting the public IP address for that machine. However, I don't understand why I am getting this message because I installed Sandbox version 2.4 as a separate instance.
Just a tip: you might have accidentally selected "None" in the second pane of the configuration:
If this is not the case, a quick advice to circumvent similar situations in the future: you can manage deployments in the Resource Group level, if you delete the resource group of Sandbox install itself, it will remove the related resources as well (like public IP).
Additionally, after a successful deployment you should check if the the "Public IP address" is present in the resource group.