Cloudwatch Event Rule doesn't invoke when source state machine fails - amazon-cloudwatch

Question

I have a step function that runs 2 separate lambdas. If the step function fails or times out, I want to get an email via SNS telling me the step function failed. I created the event rule using cloudformation and specified the statemachine ARN in the event pattern. When the step function fails, no email is sent out. If I remove the stateMachineArn parameter and run my step function, I get the failure email. I've double checked numerous times that I'm entering the correct ARN for the state machine. CF for the Event Rule is below (in YAML format). Thanks.
FailureEvent:
Type: AWS::Events::Rule
DependsOn:
- StateMachine
Properties:
Name: !Ref FailureRuleName
Description: "EventRule"
EventPattern:
detail-type:
- "Step Functions Execution Status Change"
detail:
status:
- "FAILED"
- "TIMED_OUT"
stateMachineArn: ["arn:aws:states:region:account#:stateMachine:statemachine"]
Targets:
-
Arn:
Ref: SNSARN
Id: !Ref SNSTopic

Answer 1

I did get this fixed and expanded on it to invoke a lambda that publishes a custom SNS email using a lambda. My alignment was off in my EventPattern section. See below. Thanks to #Marcin.
FailureEvent:
Type: AWS::Events::Rule
DependsOn:
- FMIStateMachine
Properties:
Description: !Ref FailureRuleDescription
Name: !Ref FailureRuleName
State: "ENABLED"
RoleArn:
'Fn::Join': ["", ['arn:aws:iam::', !Ref 'AWS::AccountId', ':role/', !Ref LambdaExecutionRole]]
EventPattern:
detail-type:
- "Step Functions Execution Status Change"
detail:
status:
- "FAILED"
- "TIMED_OUT"
stateMachineArn: [!Ref StateMachine]
Targets:
- Arn:
'Fn::Join': ["", ['arn:aws:lambda:', !Ref 'AWS::Region', ':', !Ref 'AWS::AccountId', ':function:', !Ref FailureLambda]]
Id: !Ref FailureLambda
Input: !Sub '{"failed_service": "${StateMachineName}","sns_arn": "arn:aws:sns:${AWS::Region}:${AWS::AccountId}:${SNSTopic}"}'