Amazon web services – Terraform – host for provisioner cannot be empty

I am using Terraform to provision an EC2 instance on AWS. The Terraform file is able to provision the EC2-instance, however, when it gets to the provisioner section of the script, I get the error "host for provisioner cannot be empty" despite the host value being labelled.

instance.tf file

resource "aws_key_pair" "dove-key" {
  key_name   = "dovekey"
  public_key = file("dovekey.pub")
}

resource "aws_instance" "dove-inst" {
  ami                    = var.AMIS[var.REGION]
  instance_type          = "t2.micro"
  availability_zone      = var.ZONE1
  key_name               = aws_key_pair.dove-key.key_name
  subnet_id              = "subnet-00a20e364a10aed04"
  vpc_security_group_ids = ["sg-0ddc62a99b3e5d75d"]

  tags = {
    Name    = "Dove-Instance"
    Project = "Dove"
  }

  provisioner "file" {
    source      = "web.sh"
    destination = "/tmp/web.sh"

    connection {
      type        = "ssh"
      user        = var.USER
      password    = ""
      private_key = file("dovekey")
      host        = self.public_ip
    }
  }

  provisioner "remote-exec" {
    inline = [
      "chmod u+x /tmp/web.sh",
      "sudo /tmp/web.sh"
    ]

    connection {
      type        = "ssh"
      user        = var.USER
      password    = ""
      private_key = file("dovekey")
      host        = self.public_ip
    }
  }
}

vars.tf file

variable "REGION" {
  default = "us-west-1"
}

variable "ZONE1" {
  default = "us-west-1b"
}

variable "AMIS" {
  type = map(any)
  default = {
    us-west-1 = "ami-09ab9d570789dfdd4"
    us-east-1 = "ami-0e8a34246278c21e4"
  }
}

variable "USER" {
  default = "ec2-user"

}

I expected the script to ran completely without error