Service task failure through timer

Hi All,

I’m facing issue with service task not being called when timer triggers after 5 mins or any time . it always throw error cannot find expression which I defined in service task. (first time service task gets executed successfully) and later when timer triggers and after 5 mins it doesn’t

Anyone faced this issue? any solution for this?

find attached bpmn for the same.

Can you take a look at the style guide it details common questions that if you can answer will help give some more context to your problem?