Problems with aws s3 dependency

*the project was working fine with s3 before but now i have this warnings:

warning: ExAws.request!/1 defined in application :ex_aws is used by the current application but the current application does not directly depend on :ex_aws. To fix this, you must do one of:

1. If :ex_aws is part of Erlang/Elixir, you must include it under :extra_applications inside "def application" in your mix.exs

  2. If :ex_aws is a dependency, make sure it is listed under "def deps" in your mix.exs

  3. In case you don't want to add a requirement to :ex_aws, you may optionally skip this warning by adding [xref: [exclude: ExAws]] to your "def project" in mix.exs

  lib/AWS/s3.ex:13: Project.S3.S3.upload_file_s3/1

warning: ExAws.S3.upload/4 defined in application :ex_aws_s3 is used by the current application but the current application does not directly depend on :ex_aws_s3. To fix this, you must do one of:

  1. If :ex_aws_s3 is part of Erlang/Elixir, you must include it under :extra_applications inside "def application" in your mix.exs

  2. If :ex_aws_s3 is a dependency, make sure it is listed under "def deps" in your mix.exs

  3. In case you don't want to add a requirement to :ex_aws_s3, you may optionally skip this warning by adding [xref: [exclude: ExAws.S3]] to your "def project" in mix.exs

  lib/AWS/s3.ex:12: Project.S3.S3.upload_file_s3/1

warning: ExAws.S3.Upload.stream_file/1 defined in application :ex_aws_s3 is used by the current application but the current application does not directly depend on :ex_aws_s3. To fix this, you must do one of:

  1. If :ex_aws_s3 is part of Erlang/Elixir, you must include it under :extra_applications inside "def application" in your mix.exs

  2. If :ex_aws_s3 is a dependency, make sure it is listed under "def deps" in your mix.exs

  3. In case you don't want to add a requirement to :ex_aws_s3, you may optionally skip this warning by adding [xref: [exclude: ExAws.S3.Upload]] to your "def project" in mix.exs

  lib/AWS/s3.ex:11: Project.S3.S3.upload_file_s3/1

** (exit) an exception was raised:
    ** (ArgumentError) expected a keyword list, but an entry in the list is not a two-element tuple with an atom as its first element, got: {"content-length", 0}
        (elixir 1.11.2) lib/keyword.ex:475: Keyword.keys/1
        (ex_aws 2.1.3) lib/ex_aws/auth.ex:162: ExAws.Auth.build_canonical_request/5
        (ex_aws 2.1.3) lib/ex_aws/auth.ex:145: ExAws.Auth.signature/8
        (ex_aws 2.1.3) lib/ex_aws/auth.ex:128: ExAws.Auth.auth_header/7
        (ex_aws 2.1.3) lib/ex_aws/auth.ex:46: ExAws.Auth.headers/6
        (ex_aws 2.1.3) lib/ex_aws/request.ex:29: ExAws.Request.request_and_retry/7
        (ex_aws 2.1.3) lib/ex_aws/operation/s3.ex:39: ExAws.Operation.ExAws.Operation.S3.perform/2
        (ex_aws_s3 2.0.2) lib/ex_aws/s3/upload.ex:40: ExAws.S3.Upload.initialize/2
        (ex_aws_s3 2.0.2) lib/ex_aws/s3/upload.ex:81: ExAws.Operation.ExAws.S3.Upload.perform/2
        (ex_aws 2.1.3) lib/ex_aws.ex:61: ExAws.request!/2

sometimes the message “module not available” also appears.

• i have ex_aws and ex_aws_s3 on my deps list.
• the project worked before.
• i tried some solutions given on the internet but they weren’t effective.

defp deps do
    [
      {:phoenix, "~> 1.4.0"},
      {:gettext, "~> 0.11"},
      {:plug_cowboy, "~> 2.0"},
      {:jason, "~> 1.0"},
      {:ex_aws, "~> 2.0"},
      {:ex_aws_s3, "~> 2.0"},
      {:poison, "~> 3.0"},
      {:hackney, "~> 1.9"},
      {:sweet_xml, "~> 0.6"}
    ]
  end