One of the issue most of the new AWS developers encounter is Auth failure. This is mostly because many of them use invalid Access keys or would have wrongly configured the Access key. The Access key should be configured using the steps provided in the following link.
Many of them may still find Auth failure issue even after configuring the keys.
$:>aws ec2 describe-instances –output table –region us-west-2
An error occurred (AuthFailure) when calling the DescribeInstances operation: AWS was not able to validate the provided access credentials
One of the config mostly overlooked by documentation & difficult to find is the Date configured on the client VM. Mismatches in the date can cause the above Auth failure. It would be better to set the VM date using “sudo date -s “27 JUN 2016 20:24:37” command or by setting the ntp.