Call to undefined function App\Services\exec()

=== Teste de Gráficos para Todas as Barragens === Call to undefined function App\Services\exec()

Error: Call to undefined function App\Services\exec() in file /home/salum3x/public_html/ara.copmoz.ac.mz/app/Services/ExcelChartGenerator.php on line 121 #0 /home/salum3x/public_html/ara.copmoz.ac.mz/app/Services/GraficoBarragemService.php(16): App\Services\ExcelChartGenerator::isNodeAvailable() #1 /home/salum3x/public_html/ara.copmoz.ac.mz/scripts/test-all-barragens.php(18): App\Services\GraficoBarragemService->__construct() #2 {main}