Process Model Error

Currently i am undergoing my training in Appian, where i am working on a POC named Upload Document App. I am facing issue in a process modeler where it is showing please select a record with data sync enabled. I have already synced it but it shows the error again can you help me with the problem.What I did in this application so far was uploading documents . Now what I am doing is I created a record type UDA Review so that to review the document. In that I added reviewer for reviewing the document. So I am stuck at place where i want to assign the document to the reviewer so i created process model and i am getting the error. I am  providing screen shots. So kindly help me to solve this problem.

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