Hey Ankur. Thank you for your question.

I have created a catalog item with several variables. I have created a document template that references variables from the catalog item in the ${variables.variable_name} format. I have then attempted to verify read access to the variables for the document template by using the preview function and entering a record produced from the catalog item. The values are not displayed in the preview as illustrated in the screenshot in OP.

Can you elaborate on what further details I can provide to troubleshoot the issue?