Unable to upload files to DigitalOcean Spaces using Ansible

Using the Ansible 2.4.1.0 on a Ubuntu 16.04 target, I’m unable to upload files to DigitalOcean Spaces using aws_s3 module.

This is the playbook task:

    - name: Uploading backup
      aws_s3:
        aws_access_key: "..."
        aws_secret_key: "..."
        region: nyc3
        s3_url: "https://nyc3.digitaloceanspaces.com"
        bucket: "working-bucket"
        object: "my_file.tar.gz"
        src: "my_file.tar.gz"
        mode: put
        rgw: True

and this is the error:

{
   "changed":false,
   "module_stderr":"OpenSSH_7.4p1, LibreSSL 2.5.0\r\ndebug1: Reading configuration data /Users/viniciussantana/.ssh/config\r\ndebug3: kex names ok: [diffie-hellman-group1-sha1]\r\ndebug1: Reading configuration data /etc/ssh/ssh_config\r\ndebug1: /etc/ssh/ssh_config line 53: Applying options for *\r\ndebug1: auto-mux: Trying existing master\r\ndebug2: fd 3 setting O_NONBLOCK\r\ndebug2: mux_client_hello_exchange: master version 4\r\ndebug3: mux_client_forwards: request forwardings: 0 local, 0 remote\r\ndebug3: mux_client_request_session: entering\r\ndebug3: mux_client_request_alive: entering\r\ndebug3: mux_client_request_alive: done pid = 3258\r\ndebug3: mux_client_request_session: session request sent\r\ndebug1: mux_client_request_session: master session id: 2\r\ndebug3: mux_client_read_packet: read header failed: Broken pipe\r\ndebug2: Received exit status from master 0\r\nShared connection to dev-bra1.my-company.net closed.\r\n",
   "module_stdout":"Traceback (most recent call last):\r\n  File \"/tmp/ansible_3uxtv9/ansible_module_aws_s3.py\", line 863, in <module>\r\n    main()\r\n  File \"/tmp/ansible_3uxtv9/ansible_module_aws_s3.py\", line 772, in main\r\n    upload_s3file(module, s3, bucket, obj, src, expiry, metadata, encrypt, headers)\r\n  File \"/tmp/ansible_3uxtv9/ansible_module_aws_s3.py\", line 469, in upload_s3file\r\n    s3.upload_file(Filename=src, Bucket=bucket, Key=obj, ExtraArgs=extra)\r\n  File \"/usr/local/lib/python2.7/dist-packages/boto3/s3/inject.py\", line 110, in upload_file\r\n    extra_args=ExtraArgs, callback=Callback)\r\n  File \"/usr/local/lib/python2.7/dist-packages/boto3/s3/transfer.py\", line 283, in upload_file\r\n    filename, '/'.join([bucket, key]), e))\r\nboto3.exceptions.S3UploadFailedError: Failed to upload /home/vegbrasil/backups/dev-bra1_20171121141258.tar to working-bucket/dev-bra1_20171121141258.tar: An error occurred (InvalidRequest) when calling the PutObject operation: Unknown\r\n",
   "msg":"MODULE FAILURE",
   "rc":0
}

Does anyone managed to make it work? I’m not sure if this a problem in Ansible or just something else because there’s a little of upload activity before the error happens.

(also reported in the Ansible repo)