Logstash input s3 plugin

Any idea why am i seeing the below error on using the s3 plugin.

A plugin had an unrecoverable error. Will restart this plugin.
Plugin: "s3-access-log", bucket=>"niraj-s3-log", prefix=>"logs", region=>"us-east-1", access_key_id=>"xxxxxxxxxxxxxxxxxxxxxxxxx", secret_access_key=>"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", debug=>false, codec=>"UTF-8">, use_ssl=>true, delete=>false, interval=>60, temporary_directory=>"/tmp/logstash">
Error: certificate verify failed {:level=>:error}
A plugin had an unrecoverable error. Will restart this plugin.
Plugin: "s3-access-log", bucket=>"niraj-s3-log", prefix=>"logs", region=>"us-east-1", access_key_id=>"xxxxxxxxxxxxxxxxxxxxxxxxx", secret_access_key=>"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", debug=>false, codec=>"UTF-8">, use_ssl=>true, delete=>false, interval=>60, temporary_directory=>"/tmp/logstash">
Error: certificate verify failed {:level=>:error}
^CSIGINT received. Shutting down the pipeline. {:level=>:warn}
Logstash shutdown completed

My Config:

`input {
s3 {
type => "s3-access-log"
bucket => "niraj-s3-log"
prefix => "logs"
region => "us-east-1"
access_key_id => "xxxxxxxxxxxxxxxxxxxxx"
secret_access_key => "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
use_ssl => false
codec => "json"
}
}
filter {
if [type] == "s3-access-log" {
grok {
match => { "message" => "%{S3_ACCESS_LOG}" }
}
date {
locale => "en"
match => [ "timestamp" , "dd/MMM/yyyy:HH:mm:ss Z" ]
}
}
}

output {
elasticsearch {
hosts => ["xxxxxxxxxxx:9200"]
index => "niraj-s3-logs-new-%{+YYYY.MM.dd}"
}
stdout { codec => rubydebug }
}
`