I am getting this error in element exist activity "Error getting transaction data for Transaction Number: 1. One or more errors occurred. at Source: Element Exists 'next page' " in Assignment 2: Dispatcher section

I am using the below selector
please help, thank you.

Please verify that transaction number exists and increasing every time as page numbers. You selector is right

Check your selector.
Keep the WorkItems page open in the browser and run the check element exists by defaulting the var with a value an see if it is successful.