Sum the Original estimate field for the tasks under an Epic using automation

[Najm Polaris]

Hi,

I have setup a project as "Jira work management" which is "Team managed". 

Trying to sum the Original Estimate field for all the tasks under an epic and display the total in the Epic's original estimate. 

Even though the automation shows success but it doesn't seem to work from the "For: Parent" section of the automation, up until then it works fine. 

[Sanjog Sigdel]

I have done the same for summing the story points under an EPIC and displayed the result in the EPIC using some custom fields.

Please refer to this question: https://community.atlassian.com/t5/Jira-questions/Error-while-using-lookupIssues-JIra-Smart-Value-to-sum-story/qaq-p/2363987#U2445067