title: pip install with flag "--index-url" and "--extra-index-url" from GitLab results in "ERROR: HTTP error 404 while getting"
body: <p>We are using a private GitLab Enterprise installation for storing Python modules as described in the article <a href="https://docs.gitlab.com/ee/user/packages/pypi_repository/" rel="nofollow noreferrer">PyPI packages in the Package Registry</a> <br />
  The following command was used inside containers to install the privately hosted packages:</p>
  <pre><code>pip install &lt;package_name_01&gt; &lt;package_name_02&gt; \
      --index-url https://&lt;personal_access_token_name_package_01&gt;:&lt;personal_access_token_package_01&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple \
      --extra-index-url https://&lt;personal_access_token_name_package_02&gt;:&lt;personal_access_token_package_02&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_02&gt;/packages/pypi/simple 
  </code></pre>
  <p>As seen in the example, we use packages from different GitLab projects. Therefore, we had to specify each GitLab project as <code>--index-url</code> and <code>--extra-index-url</code>. The showed solution was working but since a few days, we receive the following error:</p>
  <pre><code>pip install &lt;package_name_01&gt; &lt;package_name_02&gt; \
  &gt; --index-url https://&lt;personal_access_token_name_package_01&gt;:&lt;personal_access_token_package_01&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple \
  &gt; --extra-index-url https://&lt;personal_access_token_name_package_02&gt;:&lt;personal_access_token_package_02&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_02&gt;/packages/pypi/simple
  Looking in indexes: https://&lt;personal_access_token_name_package_01&gt;:****@gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple, https://&lt;personal_access_token_name_package_02&gt;:****@gitlab.example.com/api/v4/projects/&lt;project_id_package_02&gt;/packages/pypi/simple
  Collecting &lt;package_name_01&gt;
    ERROR: HTTP error 404 while getting https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/files/55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX/&lt;package_name_01&gt;-0.0.18-py3-none-any.whl#sha256=55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX (from https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple/&lt;package_name_01&gt;/) (requires-python:&gt;=3.6)
  ERROR: Could not install requirement &lt;package_name_01&gt;==0.0.18 from https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/files/55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX/&lt;package_name_01&gt;-0.0.18-py3-none-any.whl#sha256=55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX because of HTTP error 404 Client Error: Not Found for url: https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/files/55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX/&lt;package_name_01&gt;-0.0.18-py3-none-any.whl for URL https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/files/55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX/&lt;package_name_01&gt;-0.0.18-py3-none-any.whl#sha256=55a5d545c01aee6ef5488cb18f9d19eee9d79XXXXXXX (from https://gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple/&lt;package_name_01&gt;/) (requires-python:&gt;=3.6)
  </code></pre>
  <p>Installing the modules separately works however...</p>
  <pre><code>pip install &lt;package_name_01&gt; --index-url https://&lt;personal_access_token_name_package_01&gt;:&lt;personal_access_token_package_01&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_01&gt;/packages/pypi/simple
  pip install &lt;package_name_02&gt; --index-url https://&lt;personal_access_token_name_package_02&gt;:&lt;personal_access_token_package_02&gt;@gitlab.example.com/api/v4/projects/&lt;project_id_package_02&gt;/packages/pypi/simple
  </code></pre>
  <p>Does anyone have an idea what goes wrong here?</p>