Go to the workflow where you have the ‘Select Item’ activity targeting the ‘City’ item. Make sure that all properties, constraints, and variables used within this activity are correctly set and initialized.
Look for any variables or properties that might be null when the activity is executed. Make sure that all variables used in the activity are initialized properly and contain valid values.
Please debug the process so that it will be easy to identify the exception
The error message you’re encountering suggests that there’s a null reference exception, meaning that the program is trying to access an object or member that hasn’t been initialized. This typically occurs when you’re trying to access a property or method of an object that is currently set to Nothing (null).
Make sure the variable you are passing in Select Item activity has some value. Try to debug the process by placing a break point near Select Item activity and check whether the value has been stored or not using Immediate panel.