Your .env file will need to include the following setting keys. 
MAIL_DRIVER=smtp
MAIL_HOST=mailtrap.io
MAIL_PORT=587
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ADDRESS=null
MAIL_NAME=null
MAIL_ENCRYPTION=tls
After making changes to your mail configuration you’ll need to run the following command within your Cachet installation directory. 
php artisan config:cache

# If you experience any issues after running this command, run this too:
rm -rf bootstrap/cache/*

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Using Mailgun

Create an account with Mailgun.
  • MAIL_USERNAME should be Mailgun domain.
  • MAIL_PASSWORD should be Mailgun API Key.
Edit your .env file with the following variables. 
MAIL_DRIVER=mailgun
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=587
MAIL_USERNAME=cachethq.io
MAIL_PASSWORD=xxxx
MAIL_ADDRESS[email protected]
MAIL_NAME="Alt Three Services Limited"
MAIL_ENCRYPTION=tls
The tls encryption setting is required to have e-mails be properly delivered.

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Using Spark Post

Create an account with Spark Post. Edit your .env file with the following variables. 
MAIL_DRIVER=smtp
MAIL_HOST=smtp.sparkpostmail.com
MAIL_PORT=587
MAIL_USERNAME=SMTP_Injection
MAIL_PASSWORD=API_TOKEN
MAIL_ADDRESS[email protected]
MAIL_NAME="Alt Three Services Limited"
MAIL_ENCRYPTION=tls