CodeBuild (AWS) from CodePipeline (AWS) is not working

Looks like your policy only provides access to 'pipeline' bucket, but not to 'codepipeline-bucketSource'. Could you try giving S3 full access to the role at-least for time being so that we can debug whether this is actually an access related issue.

Finally after a lot of research I found out that it was a permission issue only. I had to change the policy as mentioned below:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "logs:CreateLogGroup",
                "logs:CreateLogStream",
                "logs:PutLogEvents"
            ],
            "Resource": [
                "*"
            ],
            "Effect": "Allow"
        },
        {
            "Action": [
                "s3:PutObject",
                "s3:GetObject",
                "s3:GetObjectVersion",
                "s3:GetBucketAcl",
                "s3:GetBucketLocation"
            ],
            "Resource": [
                "*"
            ],
            "Effect": "Allow"
        }
    ]
}

After adding this modification my code build and pipeline started working.