Issue- not able to pass arguent - "message": "Invoke SampleFlow workflow: Object reference not set to an instance of an object.",

I am trying to set transaction status for Queue Item but i am getting error as argument value is not getting passed Can someone please help me to understand, what mistake i am doing in this flow?
I am getting error in SampleFlow workflow when i try to set status for queue item.

E2EProjectFromOrchestrator - (38.9 KB)

You have 2 TrasactionItem which is variable and argument
So TransactionItem in ‘Get Trasansaction Item’ can be Variable which has value,
But TransactionItem in ‘Invoke Workflow’ can be Argument which is getting null
and vice versa
If your flowchart is main flowchart, I recommend you to delete argument