Connection Error while Data Migration of RDS (Postgres) to DynamoDB from one account to another Account in AWS

Question

I am facing Error while migrating data from RDS DB to DynamoDB with the help of AWS DMS service. I have followed below document to get the migration done Configure cross-account access to Amazon DynamoDB ,

Source -> account-A RDS(PostgresDB) Destination -> account-B DynamoDB.

Steps I have followed created source Endpoint in account A created role In Account A

{ 
"Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "sts:AssumeRole",
            "Resource": "arn:aws:iam::ACCOUNT B ID:role/DynamoDB-FullAccess"
        }
    ]
}

In Account B

AmazonDynamoDBFullAccess

AmazonDynamoDBFullAccess

but while testing connection, getting this Error "Test Endpoint failed: Application-Status: 1020912, Application-Message: Failed to connect to database. " Tried to create new EC2 instances with the same VPC, same role and policy as account A and try to connect with Account B but getting the below error

An error occurred (AccessDeniedException) when calling the DescribeTable operation: User: arn:aws:sts::<ACCOUNT_ID>:assumed-role/ ROLE is not authorized to perform: dynamodb:DescribeTable on resource: arn:aws:dynamodb:us-east-1:<ACCOUNT_ID>:table/<TABLE NAME> because no identity-based policy allows the dynamodb:DescribeTable action

can please help me this.

Tried to follow AWS DMS document to create source and target end point with mentioned role and policy in given documents.