How get report file from docker and insert to gitlab repository

I created docker which runs automated tests. I run it by gitlab script . All works except the report file. I cannot get a report file from docker and insert it to the repository. Command docker cp not working. My GitLab script and docker file:

Gitlab script:

stages:
 - test
test:
  image: docker:latest
  services:
    - name: docker:dind
      entrypoint: ["env", "-u", "DOCKER_HOST"]
      command: ["dockerd-entrypoint.sh"]
  variables:
    DOCKER_HOST: tcp://docker:2375/
    DOCKER_DRIVER: overlay2
    # See https://github.com/docker-library/docker/pull/166
    DOCKER_TLS_CERTDIR: ""
  stage: test
  before_script:
    - docker login -u "xxx" -p "yyy" docker.io
  script: 
    - docker run --name authContainer "rrr/image:0.0.1"
  after_script:
    - docker cp authContainer:/artifacts $CI_PROJECT_DIR/artifacts/
  artifacts:
    when: always
    paths:
      - $CI_PROJECT_DIR/artifacts/test-result.xml
    reports:
      junit:
         - $CI_PROJECT_DIR/artifacts/test-result.xml

Dockerfile:

FROM mcr.microsoft.com/dotnet/core/sdk:2.1

COPY /publish  /Spinelle.AutomaticTests
WORKDIR /Spinelle.AutomaticTests

RUN apt-get update -y
RUN apt install unzip

RUN wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
RUN dpkg -i google-chrome-stable_current_amd64.deb; apt-get -fy install

RUN curl https://chromedriver.storage.googleapis.com/84.0.4147.30/chromedriver_linux64.zip -o /usr/local/bin/chromedriver
RUN unzip -o /usr/local/bin/chromedriver -d /Spinelle.AutomaticTests
RUN chmod 777 /Spinelle.AutomaticTests


CMD dotnet vstest /Parallel Spinelle.AutomaticTests.dll --TestAdapterPath:. --logger:"nunit;LogFilePath=/artifacts/test-result.xml;MethodFormat=Class;FailureBodyFormat=Verbose"