Listing bucket content from instance

Hi,
I'm trying to use my S3 bucket from an instance. The command wget works and transfers files from S3 to the EC2 instance. However, aws s3 commands produce error messages such as:

aws s3 ls s3://mybucket1
Could not connect to the endpoint URL: "https://s3.us-west2.amazonaws.com/mybucket1?list-type=2&prefix=&delimiter=%2F&encoding-type=url"

Ports 80 and 44 are open.
Thanks.