AWS Beanstalk Auto-scaling Scaling Triggers with HealthyHostCount or UnhealthyHost count

Change that first option "HealthyInstanceCount" to UnHealthyInstanceCount and if there's 1 or more unhealthy, add +1 instance. If UnHealthyInstanceCount is 0, add -1 instance (take one away). Make sure your minimum is set to 1 or more (it is recommended 2 minimum, in two separate availability zones for High Availability).

Following up on this as I just had the same problem. The solution proposed by @Max is on the right track, but a slight tweak on the numbers is needed.

1) Ensure minimum instance count and maximum instance count are set as precautions

2) Set the following parameters Trigger Measurement: UnHealthyHostCount Trigger statistic: Maximum Unit of measurement: Count Upper threshold: 0 Upper breach scale increment: 1 Lower threshold: 1 Lower breach scale increment: -1