Resolve Error (AWS Free Tier and Terraform): Error launching source instance: VPCIdNotSpecified: No default VPC for this user. GroupName is only supported for EC2-Classic and default VPC.

When you use Amazon Free Tier period and want to run free EC2 instance and when you get error:

Error: Error launching source instance: VPCIdNotSpecified: No default VPC for this user. GroupName is only supported for EC2-Classic and default VPC.

You need to create Security Group resource (example for port 80 for http server):

resource "aws_security_group" "allow_http" {
  name        = "allow_http"

  ingress {
    from_port        = 80
    to_port          = 80
    protocol         = "tcp"
    cidr_blocks      = ["0.0.0.0/0"]
    ipv6_cidr_blocks = ["::/0"]
  }

  egress {
    from_port        = 0
    to_port          = 0
    protocol         = "-1"
    cidr_blocks      = ["0.0.0.0/0"]
    ipv6_cidr_blocks = ["::/0"]
  }
}