Undefined function env() in Corals

I have an issues as per below when running server with this command php artisan serve: PHP Fatal error: Uncaught Error: Call to undefined function env() in /home/app_name/public_html/app_name_staging/Corals/core/User/config/authy.php:8 Stack trace: #0 {main} thrown in /home/app_name/public_html/app_name_staging/Corals/core/User/config/authy.php on line 8. Additional info, .env file is available and dedicated server is used.Thank you.