custom task failing via App server connection from Manager Tool

Hi Team,

Custom task associated with person record is failing while running the task using app layer connection from Manager but working via DB connection.

This custom task will generate a new central account for person record.

Please suggest how to fix this issue.

Error Message : Error running script 'CCC_RegenerateAccountName_CCC_737974D62A165B4DBEAB7F27DCDB1DCD'.
at VI.DialogEngine.DialogEngine.ExecuteTask(Task task)
at VI.FormBase.Tasks.Task.Execute()
at VI.DB.Implementation.DialogMethod.Run(ISingleDbObject baseObject)
at VI.Base.SyncActions.Do(Func`1 action)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
--- End of stack trace from previous location where exception was thrown ---
at VI.DB.Entities.EntityClassificationByScripts.<RunMethodAsync>d__6.MoveNext()
at VI.DB.Scripting.ScriptRunner.Run(String key)
An error occurred in the task 'Regenerate Account Name'.
at VI.DB.Scripting.ScriptRunner.Run(String key)
at DynScripts.DlgMth_ddaQOOqdXN6AaNiHckhly20SYPC6frBr.CCC_RegenerateAccountName_CCC_737974D62A165B4DBEAB7F27DCDB1DCD()
Object reference not set to an instance of an object.
at DynScripts.DlgMth_ddaQOOqdXN6AaNiHckhly20SYPC6frBr.CCC_RegenerateAccountName_CCC_737974D62A165B4DBEAB7F27DCDB1DCD()
at DynScripts.Scripts_ddaQOOqdXN6AaNiHckhly20SYPC6frBr.CCC_BuildCentralAccount(String uid_person, String Lastname, String Firstname)
at VI.DB.CachedDataReader.Read()