laravel cache clear and config clear

// Clear application cache

php artisan cache:clear

When you fired command php artisan config:cache then it will wipe out all the env variables and env() will give null values, try running follwing command and boom there your env() again begin to catch all env variable

php artisan config:clear

https://stackoverflow.com/questions/29100877/trying-to-get-laravel-5-email-to-work