Serverless deploy throwing error saying "Resource handler returned message: "Invalid value for the parameter Policy. (Service: Sqs, Status Code: 400,"

Question

I am trying to deploy a cross account sqs policy with serverless. The serverless.yml file looks like as follows:

provider:
  name: aws
  runtime: python3.11
  region: ${opt:region, 'ap-southeast-2'}
  stage: ${opt:stage, 'dev'}
  lambdaHashingVersion: 20201221
.
.
.
.
resources:
  Resources:
    MySQSQueue:
      Type: "AWS::SQS::Queue"
      Properties:
        QueueName: ${self:custom.data-transfer-queue-name}
        RedrivePolicy:
          deadLetterTargetArn: !GetAtt DataTransferQueueDLQ.Arn
          maxReceiveCount: 3
    DataTransferQueueDLQ:
      Type: "AWS::SQS::Queue"
      Properties:
        QueueName: ${self:custom.data-transfer-queue-name}-dlq

    CrossAccountsSqsPolicy:
      Type: AWS::SQS::QueuePolicy
      Properties:
        PolicyDocument:
          Statement:
            - Sid: "Allow cross accounts access to SQS"
              Effect: "Allow"
              Principal:
                AWS: arn:aws:iam::${self:custom.env-accounts.${self:provider.stage}}:role/middleware-${self:provider.stage}-data-flow-ap-southeast-2-lambdaRole
              Resource:
                Fn::GetAtt: [MySQSQueue, Arn]
              Action:
                - sqs:ReceiveMessage
                - sqs:DeleteMessage
        Queues:
          - Ref: MySQSQueue

package:
  patterns:
    - '!**'
    - lambdas/**

custom:
  env-accounts: 
    test: 123456789012
    int: 098765432112
    int-two: 678901234567
    prod: 654321098765
  data-transfer-queue-name: data-transfering-queue
  prune:
    automatic: true
    number: 3
  warmup:
    default:
      enabled: true
  pythonRequirements:
    layer: true

I am receiving an error saying

× Stack data-transfer-int-two failed to deploy (95s)
Environment: linux, node 16.20.2, framework 3.38.0 (local), plugin 7.2.0, SDK 4.5.1
Error:
Credentials: Local, environment variables
UPDATE_FAILED: CrossAccountsSqsPolicy (AWS::SQS::QueuePolicy)
Docs:        docs.serverless.com
Resource handler returned message: "Invalid value for the parameter Policy. (Service: Sqs, Status Code: 400, Request ID: 6a17e5b2-952b-58b4-8bcb-bbe36510a7fc)" (RequestToken: b8d50c78-0035-6323-0ca7-9900040761b0, HandlerErrorCode: GeneralServiceException)
Support:     forum.serverless.com

View the full error: https://ap-southeast-2.console.aws.amazon.com/cloudformation/home?region=ap-southeast-2#/stack/detail?stackId=.............................xxxxxxx........
Bugs:        github.com/serverless/serverless/issues


3 deprecations found: run 'serverless doctor' for more details
Error: Process completed with exit code 1.

i am new to the serverless and was trying to deploy using a /deploy int-two command.

Its throwing error and exit without deploy. Please help me to find what i am doing wrong.