Railsアプリで画像データをAmazon S3にアップロードしたい。

タイトル通り、Herokuで運営してるRailsアプリで、画像データをS3に保存する機能を実装しようとしています。

下記リンクの通り、実装し、S３の設定も行ったのですが、４０３エラーが出てしまいました。
リンク

エラーメッセージはこちら。

Railsエラーメッセージ
1Excon::Error::Forbidden in TopController#input_table
2Expected(200) <=> Actual(403 Forbidden)
3excon.error.response
4  :body          => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>A4C897A83D94E024</RequestId><HostId>hFAXrdSbxzPJs1mbr1/GKcBaN5CXr6m/ywRKeWL4apfwsdLxbpCcGfa7r7cCGnlm0/LwcEKvgq4=</HostId></Error>"
5  :cookies       => [
6  ]
7  :headers       => {
8    "Connection"       => "close"
9    "Content-Type"     => "application/xml"
10    "Date"             => "Sun, 15 Sep 2019 13:19:29 GMT"
11    "Server"           => "AmazonS3"
12    "x-amz-id-2"       => "hFAXrdSbxzPJs1mbr1/GKcBaN5CXr6m/ywRKeWL4apfwsdLxbpCcGfa7r7cCGnlm0/LwcEKvgq4="
13    "x-amz-request-id" => "A4C897A83D94E024"
14  }
15  :host          => "tasuketsu-photo.s3-ap-northeast-1.amazonaws.com"
16  :local_address => "172.31.12.171"
17  :local_port    => 44590
18  :path          => "/uploads/item/image/1575/image_icon2.png"
19  :port          => 443
20  :reason_phrase => "Forbidden"
21  :remote_ip     => "52.219.68.163"
22  :status        => 403
23  :status_line   => "HTTP/1.1 403 Forbidden\r\n"
24Rails.root: /home/ec2-user/environment
25
26Application Trace | Framework Trace | Full Trace
27app/controllers/top_controller.rb:253:in `block in input_table'
28app/controllers/top_controller.rb:247:in `each'
29app/controllers/top_controller.rb:247:in `input_table'
30Request
31Parameters:
32
33{"utf8"=>"✓",
34 "authenticity_token"=>"83DBxv/C20HRLIt6LrwqwRH9UAEgc9Aw0j+oAFjkgpM=",
35 "eventname2"=>"adsfasd",
36 "explanation2"=>"",
37 "vote1"=>"1",
38 "vote2"=>"1",
39 "openpass"=>"",
40 "itemnumber2"=>"2",
41 "optionname1"=>"sadfa",
42 "file1"=>#<ActionDispatch::Http::UploadedFile:0x00000002279f28 @original_filename="image_icon2.png",
43 @content_type="image/png",
44 @headers="Content-Disposition: form-data; name=\"file1\"; filename=\"image_icon2.png\"\r\nContent-Type: image/png\r\n",
45 @tempfile=#<Tempfile:/tmp/RackMultipart20190915-21097-8dxlpc>>,
46 "URL1"=>"",
47 "memo1"=>"",
48 "optionname2"=>"asdfas",
49 "URL2"=>"",
50 "memo2"=>"",
51 "method"=>"post"}
52Show session dump
53
54Show env dump
55
56Response
57Headers:
58
59None