Sling Content Distribution not working in AEM Cloud

Requirement: Any content change under var folder for a project specific path should be replicated to publish instance. 

Approach decided: Forward sling distribution.

Post configurations deployment on cloud environment. Agent is getting created on environment along with all the configuration are also in place. For the content changes triggers are also working and request is reaching to agent, as we can see request in agent logs.

Forward sling distribution is not working in AEM cloud. we are getting below error.

org.apache.sling.distribution.common.RecoverableDistributionException: not enough rights

Although same configuration we have used on AEM 6.5 local instance and it's working fine. We are not using default agents or service users. We have added all the required ACL's permissions to the user.

We have add following configs for environments  :

Author Instance:

1. Forward agent config:

{
"name":"fwdistribution",
"title":"fwdistribution",
"details":"This agent pushes content from author to publish",
"enabled":true,
"serviceName": "distributionSubService",
"log.level":"info",
"allowed.roots":[
"/var/ugcContents"
],
"queue.processing.enabled":true,
"packageImporter.endpoints":[
"endpoint0=https://publish.adobeaemcloud.com/libs/sling/distribution/services/importers/ugcfwimporter"
],
"triggers.target":"(name=jcrsync)"
}

2. Trigger config:

{
"name":"jcrsync",
"path":"/var/ugcContents",
"serviceName":"distributionSubService",
"deep": true
}

Publish Instance:

1. Importer config:

{
"name":"ugcfwimporter",
"packageBuilder.target": "(name=default)"
}

Thanks in advance for any help.