RailsのMicropostのアップロードで、AWS S3に画像データが保存できず、エラーになってしまう。

前提・実現したいこと

現在、Ruby on Railsのチュートリアルで第１３章を終えてHerokuにアップロードしたのですが、テキストは問題ないのですが画像が
保存されず、herokuエラーが出てしまいます。いろいろ他の方の投稿やサイトをチェックしているのですが、複雑でわからず困っています。
バケットポリシーの設定も分りづらく、詳しい方いらっしゃいましたらアドバイスをお願いします。

発生している問題・エラーメッセージ

以下、heroku logs です。　<message>Access Denied</message>と出ているのでアクセス拒否されてるかとは思うのですが・・。

9SLILcsAveIYonPPSAAimWboQG9wMcK1ZVPvVyBZi4P+oPen/L5edCU/kldSWBNGcS5Tg==", "micropost"=>{"content"=>"????\r\n", "picture"=>#<ActionDispatch::Http::UploadedFile:0x00005582daa99130 @tempfile=#<Tempfile:/tmp/RackMultipart20200524-4-10t908m.JPG>, @original_filename="IMG_1485.JPG", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"micropost[picture]\"; filename=\"IMG_1485.JPG\"\r\nContent-Type: image/jpeg\r\n">}, "commit"=>"Post"}
2020-05-24T11:07:52.158888+00:00 app[web.1]: D, [2020-05-24T11:07:52.158821 #4] DEBUG -- : [01104a90-9238-4b92-93ad-ac2461c70685]   User Load (1.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2  [["id", 101], ["LIMIT", 1]]
2020-05-24T11:07:52.245948+00:00 app[web.1]: D, [2020-05-24T11:07:52.245826 #4] DEBUG -- : [01104a90-9238-4b92-93ad-ac2461c70685]    (1.1ms)  BEGIN
2020-05-24T11:07:52.249838+00:00 app[web.1]: D, [2020-05-24T11:07:52.249732 #4] DEBUG -- : [01104a90-9238-4b92-93ad-ac2461c70685]   SQL (2.0ms)  INSERT INTO "microposts" ("content", "user_id", "created_at", "updated_at", "picture") VALUES ($1, $2, $3, $4, $5) RETURNING "id"  [["content", "????\r\n"], ["user_id", 101], ["created_at", "2020-05-24 11:07:52.247002"], ["updated_at", "2020-05-24 11:07:52.247002"], ["picture", "IMG_1485.JPG"]]
2020-05-24T11:07:56.369267+00:00 heroku[router]: at=info method=POST path="/microposts" host=salty-refuge-73442.herokuapp.com request_id=01104a90-9238-4b92-93ad-ac2461c70685 fwd="182.166.166.94" dyno=web.1 connect=0ms service=4802ms status=500 bytes=1891 protocol=https
2020-05-24T11:07:56.370813+00:00 app[web.1]: D, [2020-05-24T11:07:56.370686 #4] DEBUG -- : [01104a90-9238-4b92-93ad-ac2461c70685]    (1.2ms)  ROLLBACK
2020-05-24T11:07:56.371321+00:00 app[web.1]: I, [2020-05-24T11:07:56.371226 #4]  INFO -- : [01104a90-9238-4b92-93ad-ac2461c70685] Completed 500 Internal Server Error in 4216ms (ActiveRecord: 5.4ms)
2020-05-24T11:07:56.371957+00:00 app[web.1]: F, [2020-05-24T11:07:56.371897 #4] FATAL -- : [01104a90-9238-4b92-93ad-ac2461c70685]
2020-05-24T11:07:56.372019+00:00 app[web.1]: F, [2020-05-24T11:07:56.371966 #4] FATAL -- : [01104a90-9238-4b92-93ad-ac2461c70685] Excon::Error::Forbidden (Expected(200) <=> Actual(403 Forbidden)
2020-05-24T11:07:56.372020+00:00 app[web.1]: excon.error.response
2020-05-24T11:07:56.372021+00:00 app[web.1]: :body          => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>60DD5D0631A60CE9</RequestId><HostId>5Vo6QOFPDsqudNt/hJl4zPbYrVP4IRSe7pPK/0IhFyvFnRvLZ4FHoBrQbga+C8Fcv8qNEhElx/0=</HostId></Error>"
2020-05-24T11:07:56.372021+00:00 app[web.1]: :cookies       => [
2020-05-24T11:07:56.372021+00:00 app[web.1]: ]
2020-05-24T11:07:56.372022+00:00 app[web.1]: :headers       => {
2020-05-24T11:07:56.372022+00:00 app[web.1]: "Connection"       => "close"
2020-05-24T11:07:56.372023+00:00 app[web.1]: "Content-Type"     => "application/xml"
2020-05-24T11:07:56.372023+00:00 app[web.1]: "Date"             => "Sun, 24 May 2020 11:07:56 GMT"
2020-05-24T11:07:56.372023+00:00 app[web.1]: "Server"           => "AmazonS3"
2020-05-24T11:07:56.372024+00:00 app[web.1]: "x-amz-id-2"       => "5Vo6QOFPDsqudNt/hJl4zPbYrVP4IRSe7pPK/0IhFyvFnRvLZ4FHoBrQbga+C8Fcv8qNEhElx/0="
2020-05-24T11:07:56.372024+00:00 app[web.1]: "x-amz-request-id" => "60DD5D0631A60CE9"
2020-05-24T11:07:56.372025+00:00 app[web.1]: }
2020-05-24T11:07:56.372025+00:00 app[web.1]: :host          => "helo2698.s3-ap-northeast-1.amazonaws.com"
2020-05-24T11:07:56.372025+00:00 app[web.1]: :local_address => "172.16.18.254"
2020-05-24T11:07:56.372025+00:00 app[web.1]: :local_port    => 56496
2020-05-24T11:07:56.372026+00:00 app[web.1]: :path          => "/uploads/micropost/picture/29208/IMG_1485.JPG"
2020-05-24T11:07:56.372026+00:00 app[web.1]: :port          => 443
2020-05-24T11:07:56.372026+00:00 app[web.1]: :reason_phrase => "Forbidden"
2020-05-24T11:07:56.372026+00:00 app[web.1]: :remote_ip     => "52.219.0.67"
2020-05-24T11:07:56.372027+00:00 app[web.1]: :status        => 403
2020-05-24T11:07:56.372027+00:00 app[web.1]: :status_line   => "HTTP/1.1 403 Forbidden\r\n"
2020-05-24T11:07:56.372027+00:00 app[web.1]: ):
2020-05-24T11:07:56.372069+00:00 app[web.1]: F, [2020-05-24T11:07:56.372022 #4] FATAL -- : [01104a90-9238-4b92-93ad-ac2461c70685]
2020-05-24T11:07:56.372118+00:00 app[web.1]: F, [2020-05-24T11:07:56.372076 #4] FATAL -- : [01104a90-9238-4b92-93ad-ac2461c70685] app/controllers/microposts_controller.rb:7:in `create'