Symfony \ Component \ Process \ Exception \ ProcessSignaledException The process has been signaled with signal "4"

getting following error when downloading PDF file earlier it was working fine -

Symfony \ Component \ Process \ Exception \ ProcessSignaledException The process has been signaled with signal "4".

below are the codes -

$pdf = PDF::loadView('expense.approve_expense', $data);

\Illuminate\Support\Facades\Storage::makeDirectory('public/email', 777);

$pdf->download($employeeDetails['claim_code'] . '.pdf');

via Chebli Mohamed