Backup to AWS S3 Server

I have setup a AWS S3 backup.Double checked my Bucket name ,AWS access key and secret ,but i get
on running the backup

Whoops\Exception\ErrorException: S3::listBuckets(): [AccessDenied] Access Denied in file /var/www/html/admin/modules/backup/functions.inc/s3.php on line 375
Stack trace:

  1. Whoops\Exception\ErrorException->() /var/www/html/admin/modules/backup/functions.inc/s3.php:375
  2. Whoops\Run->handleError() :0
  3. trigger_error() /var/www/html/admin/modules/backup/functions.inc/s3.php:375
  4. S3->__triggerError() /var/www/html/admin/modules/backup/functions.inc/s3.php:394
  5. S3->listBuckets() /var/www/html/admin/modules/backup/functions.inc/class.backup.php:501
  6. FreePBX\modules\Backup\Backup->store_backup() /var/www/html/admin/modules/backup/bin/backup.php:145

Am i missing something ?

I found the solution of this issue.It had to give permissions to the iam user of AWS.
But now i am facing another issue wich i think ts a bug,
When running the backup i get

Whoops\Exception\ErrorException: S3::putObject(): [InvalidRequest] The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256. in file

After a google search i found that
the AWS4-HMAC-SHA256, also known as “V4,” is one of two authentication schemes in S3.
US-Standard, and many – but not all – other regions, also support the other, older scheme, V2.
According to http://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html … new S3 regions deployed after January, 2014 will only support V4.
I am using the Frankfurt Region and
Since Frankfurt was introduced late in 2014, it apparently does not support V2, which is what this error suggests i am using.
Shoul i report it as a bug ?

There is already a bug report for this issue which can be found at http://issues.freepbx.org/browse/FREEPBX-12996. Feel free to add yourself as a watcher to be notified of changes to the ticket.

Its my bug report.Thank you