The error "Connection refused" can occur due to several reasons but in the context of running a script through Calm on VM, it is most likely caused by firewall restrictions or insufficient permissions. Option A suggests that the VM port is not allowed by the firewall, meaning that the firewall settings are preventing the connection. This could be because specific ports needed for the script to run are being blocked. Option B indicates that the credentials have insufficient permissions, meaning that the user or system trying to execute the script does not have the necessary permissions to establish a connection. Option C is unlikely because the VM should be ready before the script is executed. Option D is possible but not specific enough to explain the connection issue. Reference: You can find more information about this topic in the following sources:
Nutanix Certified Professional - Multicloud Automation (NCP-MCA) Exam Blueprint Guide, Section 3 - Validate Blueprints, Runbooks, Playbooks, and Automation Settings, page 9 Nutanix Multicloud Automation Administration (NMCAA), Module 5 - Troubleshooting, Lesson 1 - Troubleshooting Calm, page 5-4

To update the running configuration for a multi-VM application in AWS using the Manage tab for the application in Calm, the administrator needs to provide the provider information for the AWS account. This includes the access key, secret key, region, and VPC ID. If the provider information is missing, the administrator will not be able to perform any actions on the application from Calm. Reference: Nutanix Certified Professional - Multicloud Automation (NCP-MCA) Exam Blueprint Guide, page 16, section 4.1.1.

The Developer role is the most appropriate role for the end user who needs to modify the blueprints for the project. The Developer role allows the user to create, edit, and delete blueprints and runbooks within the project, as well as launch and manage applications from the Marketplace. The Developer role does not have the privileges to create or manage projects, users, roles, or categories, which are reserved for the Project Admin role. The Consumer role only allows the user to launch and manage applications from the Marketplace, but not to modify the blueprints or runbooks. The Operator role allows the user to monitor and manage the infrastructure and applications within the project, but not to create or edit the blueprints or runbooks.
Reference:
Nutanix Certified Professional - Multicloud Automation (NCP-MCA) v6.5, Section 1 - Describe and Differentiate Automation Concepts and Principles, Objective 1.5 - Identify the capabilities of Projects Nutanix Multicloud Automation Administration (NMCAA), Module 3 - Self-Service Projects, Lesson 3.1 - Project Roles and Permissions

To ensure the VMs are properly remediated, the Playbook actions should be added in the following order: Take a VM Snapshot, VM add Memory, Resolve Alert. This is because Memory Hot Add allows the administrator to increase the memory allocation of a running VM without powering it off. Taking a VM snapshot before adding memory provides a backup point in case of any issues. Resolving the alert after adding memory clears the notification and updates the status of the VM. Powering off the VM is not necessary and may cause downtime or disruption to the applications running on the VM. Reference: Nutanix Certified Professional - Multicloud Automation (NCP-MCA) Exam Blueprint Guide, page 11; Nutanix Calm SaaS User Guide, section 4.2.3.

The Consumer can ensure all underlying VMs are deleted with the removal of the application by going to the Manage tab of the application and selecting the Hard Delete action. This option will delete the application and all its associated resources from the Nutanix platform, without leaving any traces or backups. This option is useful when the application is no longer needed or has to be removed for compliance reasons.
From the Applications page, selecting the checkbox next to the application and selecting Delete from the action's menu will not delete all underlying VMs. This option will only delete the application from the Calm UI, but not from the Nutanix platform. The application and its resources will still be available in the Nutanix cluster and can be restored from the Calm UI using the Restore action.
From the Marketplace page, selecting the checkbox next to the application and selecting Delete from the actions menu will not delete the application or its underlying VMs. This option will only delete the application from the Marketplace, but not from the Calm UI or the Nutanix platform. The application and its resources will still be available in the Calm UI and the Nutanix cluster.
Going to the Manage tab of the application and selecting the Delete action will also not delete all underlying VMs. This option will only delete the application from the Calm UI, but not from the Nutanix platform. The application and its resources will still be available in the Nutanix cluster and can be restored from the Calm UI using the Restore action.
Reference:
Nutanix Calm User Guide: Chapter 6: Managing Applications
Nutanix Calm DSL User Guide: Chapter 4: Blueprints
Nutanix Certified Professional - Multicloud Automation (NCP-MCA) Exam Blueprint Guide: Section 2: Deploy and Configure Self-service and Related Components