Boto [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed while connecting to S3

Probably your bucket name contains a dot, that's why ssl certificate verification fails. This is quite a frequent problem, see this github issue for example.

Don't use an insecure connection (is_secure=False), instead use OrdinaryCallingFormat:

import boto
conn = boto.s3.connect_to_region('eu-west-1', calling_format=boto.s3.connection.OrdinaryCallingFormat())
bucket = conn.get_bucket(your_bucket)

You probably need to update your AWS Region, e.g. us-east-1

I found a way,

used is_secure=False in connect_s3().

In boto3, if you are using the s3 client, use verify=False when creating the s3 client. For eg:

s3 = boto3.client('s3', verify=False)

As mentioned on boto3 documentation, this only turns off validation of SSL certificates. SSL will still be used (unless use_ssl is False), but SSL certificates will not be verified.

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/core/session.html