PHPExcel日期验证提供未知错误

I am using date validation on excel sheet through phpexcel but every time it says wrong date.

but when i click on validation on my excel sheet and does not do anything just click on 'ok' the validation start working.

    $objValidation = $objPHPExcel->getActiveSheet()->getCell('G'.$i)->getDataValidation();
    $objValidation->setType( PHPExcel_Cell_DataValidation::TYPE_DATE );
    $objValidation->setErrorStyle( PHPExcel_Cell_DataValidation::STYLE_STOP );
    $objValidation->setAllowBlank(false);
    $objValidation->setShowErrorMessage(true);
    $objValidation->setErrorTitle('Invalid D.O.B');
    $objValidation->setError('Please Enter a valid D.O.B');
    $objValidation->setFormula1('"'.$minDob.'"');
    $objValidation->setFormula2('"'.$maxDob.'"');

this is my code please help.

the code seems to work fine as validation tab on excel shows the correct excel. but somehow it does not work. and by simply clicking on 'ok' it starts to work again.