How do I resolve the "Route did not stabilize in expected time" error in AWS CloudFormation?

Short description

You must specify one of the following targets for the route assigned to your route table in your Amazon Virtual Private Cloud (Amazon VPC):

• Internet gateway or virtual private gateway
• NAT instance
• NAT gateway
• VPC peering connection
• Network interface
• Egress-only internet gateway

If you set any property of your AWS::EC2::Route type (your target) to an incorrect value, then you receive the "Route did not stabilize in expected time" error.

For example, you receive this error if you incorrectly set the value of the NatGatewayId property to the GatewayId property, as shown in the following code example:

MyRoute ": {
  "Type": "AWS::EC2::Route",
  "Properties": {
    "DestinationCidrBlock": "0.0.0.0/0",
    "GatewayId": "nat-0a12bc456789de0fg",
    "RouteTableId": {
      "Ref": "MyRouteTable"
    }
  }
}

Resolution

Assign the correct value to the corresponding property. See the following examples:

"GatewayId" : "igw-eaad4883"

-or-

"NatGatewayId" : "nat-0a12bc456789de0fg"

For more information on a stack failure, check the AWS CloudTrail events that correspond to the failure.