未定义的索引：当用户通过银行付款时的email_driver

Question

Im getting this message when trying to pay via bank information in Laravel 4.2. Sending emails with mailgun works fine, so I m wondering what could be the reason why this happens? My email credentials are listed in my enviroment file:

'email_driver'          => 'mailgun',
'email_smtp_host'       => 'smtp.mailgun.org',
'email_smtp_port'       =>  587,
'email_from_address'    => '.....',
'email_from_name'       => '.....',
'email_encryption'      => 'tls',
'email_username'        => 'postmaster@......mailgun.org',
'email_password'        => '.......',
'email_pretend'         =>  false

Would appreciate any help!