User data synchronization exception

Hi All,

We are using sling distribution agent feature for publishing user data to all publisher instances but getting below exception.

Caused by: org.apache.jackrabbit.oak.api.CommitFailedException: OakConstraint0021: /home/users/a/eiTRubAYMWwDWGJVfOA6/.tokens/2017-03-07T15.26.18.287Z[[rep:Token]]: Mandatory property rep:token.key not found in a new node

We have requirement that once user token created in any publish instance that should be distributed to all available publish instances to keep user session active if connected to other publish instances.