I received a “Command cannot be executed” email. What should I check?

Check followings for the instance:
 
EC2 instances

• EC2 instance status is “Active”

Systems Manager

• The instance is online for “Managed Instance”
• amazon-ssm-agent service is Active
• No failure occurred in the history of “Run command”

IAM Role

• Appropriate permission has been granted

 Once AppKeeper confirms that the commands can be executed, it resumes the monitoring automatically.