Hi athirut,

May I know if there is an error showing up in the management ?

You may also refer to the below documentation 

https://help.nintex.com/en-US/k2five/userguide/5.4/default.htm#K2-Workflow-Designer/Use/Toolbox/Basic/CallSubWorkflow/Call-SubWorkflow.htm?TocPath=Create%257CWorkflows%257CUsing%2520the%2520K2%2520Workflow%2520Designer%257CToolbox%257CBasic%257C_____5

Should you feel that this post is of use and or an accurate solution to the raised question, I kindly encourage you to mark it as such 
using the 'Best Answer', 'Like' andor ‘Me Too’ options.

Cheers,
Kate

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