The class needs to be applied on the parent, which is <nav>

Edit: Since there is more content inside the nav, the justify-content-end class would not work as intended. You need to use ml-auto

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/>

<nav class="navbar navbar-expand-lg navbar-light bg-light col-12">
    <h1>H1 tag</h1>
    <ul class="nav ml-auto">
        <li class="nav-item">
            <a class="nav-link active" href="#">Active</a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Link</a>
        </li>
        <li class="nav-item">
            <a class="nav-link disabled" href="#">Disabled</a>
        </li>
    </ul>
</nav>

Answer from Anurag Srivastava on Stack Overflow
🌐
Bootstrap
getbootstrap.com › docs › 4.0 › utilities › flex
Flex · Bootstrap
Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, or around.
🌐
Bootstrap
getbootstrap.com › docs › 5.0 › utilities › flex
Flex · Bootstrap v5.0
Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, around, or evenly.
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Bootstrap Shuffle
bootstrapshuffle.com › classes › flexbox › justify-content-*-end
justify-content-*-end - Bootstrap CSS class
<div class="d-flex justify-content-end"> <div class="p-2">Flex item 1</div> <div class="p-2">Flex item 2</div> <div class="p-2">Flex item 3</div> </div> <!-- responsive variations --> <div class="d-flex justify-content-sm-end">...</div> <div class="d-flex justify-content-md-end">...</div> <div class="d-flex justify-content-lg-end">...</div> <div class="d-flex justify-content-xl-end">...</div>Copy code ... You don't need to remember all CSS classes. Just use the Bootstrap Editor instead.
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W3Schools
w3schools.com › bootstrap4 › bootstrap_flex.asp
Bootstrap 4 Flex
Use the .justify-content-* classes to change the alignment of flex items. Valid classes are start (default), end, center, between or around:
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GeeksforGeeks
geeksforgeeks.org › bootstrap › bootstrap-5-flex-justify-content
Bootstrap 5 Flex Justify Content - GeeksforGeeks
April 10, 2024 - Example 1: In this example, we change the alignment of the elements on the main axis using justify-content-start and justify-content-end classes. ... <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link href= "https://cdn.jsdelivr.net/npm/bootstrap@5.2.2/dist/css/bootstrap.min.css" rel="stylesheet"> <script src= "https://cdn.jsdelivr.net/npm/bootstrap@5.2.2/dist/js/bootstrap.min.js"> </script> </head> <body> <div class="container text-center "> <h1 class=
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Bootstrap
getbootstrap.com › docs › 4.6 › utilities › flex
Flex · Bootstrap v4.6
Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, or around.
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TutorialsPoint
tutorialspoint.com › Bootstrap-4-justify-content-end-class
Bootstrap 4 .justify-content-*-end class
BootstrapWeb DevelopmentCSS Framework · To justify the flex items on the end, use the justify-content-end class. To justify the flex items on the end, on different screen sizes, use the justify-content-*-end class. The flex items justified at the end would be visible like the following on ...
Find elsewhere
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Shuffle
shuffle.dev › bootstrap › classes › flexbox › justify-content-end
Bootstrap CSS class: justify-content-end - Shuffle
Bootstrap CSS class justify-content-end with source code and live preview. You can copy the example and paste it into your project or use the Shuffle editor and not write code by hand!
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FastBootstrap
fastbootstrap.com › docs › justify-content
Bootstrap Justify Content CSS - FastBootstrap
Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, around, or evenly.
Top answer
1 of 2
2

I have changed your code a little to get the desired effect.

On <div class="row"> i removed some unneeded styles. and on the <div class="col"> i changed it to col-4 to set the width. Since bootstrap works in a frame of 12. 4 + 4 leaves 4 short so thats the space thats being filled with justify-content-between. I also deleted your css since it was not needed.

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<body class="d-flex flex-column min-vh-100">
  <!-- -->
  <nav class="navbar navbar-light navbar-expand-md bg-light">
    <div class="container-fluid">
      <a class="navbar-brand" href="#">
        <img src="img/logo.svg" alt="">
      </a>
      <!-- -->
      <div class="navbar-nav d-none d-md-flex">
        <a class="nav-link active" aria-current="page" href="#">Home</a>
        <a class="nav-link" href="#">A</a>
        <a class="nav-link" href="#">B</a>
        <a class="nav-link" href="#">C</a>
        <a class="nav-link" href="#">D</a>
        <a class="nav-link" href="#">E</a>
      </div>
      <!-- -->
      <span>
        <a href="https://twitter.com/" rel="nofollow noopener noreferrer"><i
            class="fab fa-twitter mx-2 gstwitterblue"></i></a>
        <a href="https://www.linkedin.com/"
          rel="nofollow noopener noreferrer"><i class="fab fa-linkedin mx-2 gslinkedinblue"></i></a>
      </span>
    </div>
  </nav>
  <main class="flex-fill">
     <div class="container d-none d-md-flex flex-md-row">
      <div class="row justify-content-between">
        <div class="col-4">
          <div class="card">
            <div class="ratio ratio-16x9">
              <iframe src="https://www.youtube-nocookie.com/embed/wm48_VrbB4Q?rel=0" allowfullscreen></iframe>
            </div>
            <div class="card-body">
              <p class="card-text">

               Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam efficitur orci malesuada sem lacinia, vitae tempor tellus auctor. Sed elementum iaculis quam ac consectetur. Nam ac laoreet est, ut placerat arcu. Ut viverra, quam vitae gravida ornare, arcu felis elementum elit, a pulvinar lacus augue ac nisl. Nunc tincidunt ultricies luctus. Donec et congue ex. Curabitur lacinia scelerisque imperdiet. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aenean ultricies, mauris at ultricies dapibus, urna nisl ullamcorper libero, ac dictum ex neque sed ante. Pellentesque luctus nibh libero, consequat vulputate eros porttitor vitae.</p>
            </div>
          </div>
        </div>
      <div class="col-4">
        <div class="card gscustomwidth">
          <div class="ratio ratio-16x9">
            <iframe src="https://www.youtube-nocookie.com/embed/wm48_VrbB4Q?rel=0" allowfullscreen></iframe>
          </div>
          <div class="card-body">
            <p class="card-text">

            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam efficitur orci malesuada sem lacinia, vitae tempor tellus auctor. Sed elementum iaculis quam ac consectetur. Nam ac laoreet est, ut placerat arcu. Ut viverra, quam vitae gravida ornare, arcu felis elementum elit, a pulvinar lacus augue ac nisl. Nunc tincidunt ultricies luctus. Donec et congue ex. Curabitur lacinia scelerisque imperdiet. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aenean ultricies, mauris at ultricies dapibus, urna nisl ullamcorper libero, ac dictum ex neque sed ante. Pellentesque luctus nibh libero, consequat vulputate eros porttitor vitae. </p>
          </div>
        </div>
      </div>
    </div>
  </div>
    </main>
  <!-- Standard Footer -->
  <footer class="bg-light py-3 d-none d-md-flex">
    <div class="container d-flex justify-content-between">
      <span class="text-dark fw-lighter">Copyright  2020 Foobar Ltd. All rights reserved.</span>
      <span class="text-dark fw-lighter"><a href="#" class="text-reset text-decoration-none">Legal
          Information</a></span>
    </div>
  </footer>
  </body>

2 of 2
2

The reason what you want doesn't happen is because you're not giving the row div a full width. From your code, add w-100 to the following div:

<div class="row row-cols-1 row-cols-md-2 justify-content-between">
🌐
W3Schools
w3schools.com › bootstrap5 › bootstrap_flex.php
Bootstrap 5 Flex
Use the .justify-content-* classes to change the alignment of flex items. Valid classes are start (default), end, center, between or around:
🌐
Educative
educative.io › answers › what-is-justify-content-in-bootstrap-4
What is justify-content in Bootstrap 4?
Here are a few of its properties: justify-content-start: Lists all items at the start of the flex-box container. justify-content-end: Lists all items at the end of the flex-box container.
🌐
Bootstrap
getbootstrap.com › docs › 5.3 › layout › columns
Columns · Bootstrap v5.3
<div class="container text-center"> <div class="row"> <div class="col align-self-start"> One of three columns </div> <div class="col align-self-center"> One of three columns </div> <div class="col align-self-end"> One of three columns </div> </div> </div> Change the horizontal alignment with any of the responsive justify-content-* classes.
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Bootstrap Shuffle
bootstrapshuffle.com › classes › flexbox › justify-content-sm-end
justify-content-sm-end - Bootstrap CSS class
Bootstrap CSS class justify-content-sm-end with source code and live preview. You can copy our examples and paste them into your project!
🌐
Shuffle
shuffle.dev › bootstrap › classes › flexbox › justify-content-md-end
Bootstrap CSS class: justify-content-md-end
Bootstrap CSS class justify-content-md-end with source code and live preview. You can copy the example and paste it into your project or use the Shuffle editor and not write code by hand!
🌐
Shuffle
shuffle.dev › bootstrap › classes › flexbox › justify-content-lg-end
Bootstrap CSS class: justify-content-lg-end - Shuffle
Bootstrap CSS class justify-content-lg-end with source code and live preview. You can copy the example and paste it into your project or use the Shuffle editor and not write code by hand!
🌐
GitHub
github.com › orgs › twbs › discussions › 36773
".justify-content-end" to align menu links to right side not working · twbs · Discussion #36773
September 4, 2023 - I'm designing a website and just shifted to incorporating Bootstrap 5 and have made a navbar from the Bootstrap Docs and as by default the menu was left aligned right after the brand image. To change the direction of the menu from left to right, Bootstrap has a .justify-content-end class but adding it to my