<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Third Party Services
    |--------------------------------------------------------------------------
    |
    | This file is for storing the credentials for third party services such
    | as Stripe, Mailgun, SparkPost and others. This file provides a sane
    | default location for this type of information, allowing packages
    | to have a conventional place to find your various credentials.
    |
    */

    'mailgun' => [
        'domain' => env('MAILGUN_DOMAIN'),
        'secret' => env('MAILGUN_SECRET'),
    ],

    'ses' => [
        'key' => env('SES_KEY'),
        'secret' => env('SES_SECRET'),
        'region' => 'us-east-1',
    ],

    'sparkpost' => [
        'secret' => env('SPARKPOST_SECRET'),
    ],

    'stripe' => [
        'model' => App\User::class,
        'key' => env('STRIPE_KEY'),
        'secret' => env('STRIPE_SECRET'),
    ],

];

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Third Party Services
    |--------------------------------------------------------------------------
    |
    | This file is for storing the credentials for third party services such
    | as Stripe, Mailgun, SparkPost and others. This file provides a sane
    | default location for this type of information, allowing packages
    | to have a conventional place to find your various credentials.
    |
    */

    'mailgun' => [
        'domain' => env('MAILGUN_DOMAIN'),
        'secret' => env('MAILGUN_SECRET'),
    ],

    'ses' => [
        'key' => env('SES_KEY'),
        'secret' => env('SES_SECRET'),
        'region' => env('SES_REGION','us-east-1'),
    ],

    'sparkpost' => [
        'secret' => env('SPARKPOST_SECRET'),
    ],

    'stripe' => [
        'model' => App\User::class,
        'key' => env('STRIPE_KEY'),
        'secret' => env('STRIPE_SECRET'),
    ],

];

Add SES_REGION to local environment file
Add SES_REGION to local environment file

The region used by SES was hardcoded into the config file, when all other values were set as environment variables. Tweaked to keep the region consistent with other config options