amazon-ebs: WinRM connection error unknown error Post "https://<ip>:5986/wsman": EOF

[zamanh]

Overview of the Issue

Getting an unusual error when I am trying to connect to a Windows instance from an already existing AMI.

12:42:39:342 INFO: [win2012_x64_aws_std_en_us] [packer] 2025/10/08 12:42:39 packer-plugin-amazon_v1.5.0_x5.0_windows_amd64.exe plugin: 2025/10/08 12:42:39 Using host value: 10.237.78.166
12:42:39:345 INFO: [win2012_x64_aws_std_en_us] [packer] 2025/10/08 12:42:39 packer-plugin-amazon_v1.5.0_x5.0_windows_amd64.exe plugin: 2025/10/08 12:42:39 [INFO] Attempting WinRM connection...
12:42:39:347 INFO: [win2012_x64_aws_std_en_us] [packer] 2025/10/08 12:42:39 packer-plugin-amazon_v1.5.0_x5.0_windows_amd64.exe plugin: 2025/10/08 12:42:39 [DEBUG] connecting to remote shell using WinRM
12:43:24:397 INFO: [win2012_x64_aws_std_en_us] [packer] 2025/10/08 12:43:24 packer-plugin-amazon_v1.5.0_x5.0_windows_amd64.exe plugin: 2025/10/08 12:43:24 [ERROR] connection error: unknown error Post "https://10.237.78.166:5986/wsman": EOF

Reproduction Steps

• Attempt a packer build

Plugin and Packer version

• Packer v1.14.2
• Plugin version: 1.5.0

Simplified Packer Buildfile

Details

source "amazon-ebs" "win-ami" {
  region =  var.region
  vpc_id = var.vpc_id
  subnet_id = var.subnet
  security_group_id = var.security_group

  source_ami = var.ami_id  # use an existing Windows AMI

  instance_type =  var.instance_type

  communicator = "winrm"
  winrm_username       = var.ami_user
  winrm_password       = "${var.admin_password}"
  winrm_use_ssl        = true
  winrm_timeout        = "30m"
  winrm_port           = 5986
  winrm_insecure       = true 

  ssh_interface = "private_ip"
  ssh_username =  var.ami_user

  ami_name = "${var.vm_name}-{{uuid}}-{{timestamp}}"
  ami_description = "Packer-Import process: ${var.display_name}"
  ami_regions = [var.region]

  launch_block_device_mappings {
    device_name = var.ami_device_name
    volume_size = var.disk_size / 1024
    volume_type = "gp3"
    delete_on_termination = true
  }
}

Operating system and Environment details

• Windows 11 25H2 (Powershell 7.5.3)
• Ubuntu 24.04 (under WSL2 gives me the same issue too)