SignatureDoesNotMatch error when using SES with wp ses plugin

I have a python program sending emails with success using my global access key and secret key.

I try to use these same credentials in the settings interface of the wordpress ses plugin. Here is interface errors:

In the apache error log i get the error:

PHP Warning: SimpleEmailService::sendEmail(): Sender - SignatureDoesNotMatch: The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.\nRequest Id: b5fb7d11-8f84-11e4-a5cf-f71ae5f59c02\n in /var/www/html/wp-content/plugins/wp-ses/ses.class.0.8.4.php on line 383, referer: http://example.com/wp-admin/options-general.php?page=wp-ses/wp-ses.php