I am not able to delete task from Account. I am getting below error on page
Validation Errors While Saving Record(s) There were custom validation error(s) encountered while saving the affected record(s).
The first validation error encountered was "Apex trigger TaskTrigger caused an unexpected exception, contact your administrator: TaskTrigger: execution of AfterDelete caused by: System.NullPointerException: Attempt to de-reference a null object: ()".
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