Quick resolution: Stop & Start the instance
For those interested in the whole story …
We had an instance go down and upon logging into the AWS EC2 Management Console, we were confronted with this scarry message
Naturally, we clicked “Troubleshoot”
The Resolution seemed simple enough – Just Stop & Start the instance; however, stopping the instance didn’t seem to work – It just hung at and instance state of “Stopping”
After waiting what seemed an eternity (~45 minute), the instance finally stopped, at which time we were able to start it back up – effectively clearing the issue of the instance being unreachable as well as its retirement.