the first step is to check the value of the src attribute of your tag so that it displays the source code of your page where your video is.

   <div id="main-video" class="embed-responsive embed-responsive-16by9">
      <video  playsinline webkit-playsinline="webkit-playsinline" preload="auto" poster="..." class="embed-responsive-item video-js vjs-default-skin vjs-big-play-centered vjs-16-9" id="mainVideo">
         <source src="https://mydomain.com/videos/video_221105001605_v2e82/res720/index.m3u8?token=..." type="application/x-mpegURL" label="720p HD" res="720">
         <source src="https://mydomain.com/videos/video_221105001605_v2e82/res480/index.m3u8?token=..." type="application/x-mpegURL" label="480p" res="480">
         <source src="https://mydomain.com/videos/video_221105001605_v2e82/index.m3u8?token=..." type="application/x-mpegURL" label="AUTO" res="auto">
      </video>
   </div>

This means your video does not exist in your videos directory, double check directly in your server drive if that is the case

• If your video is the embed type, you have to check with the place where you embed the video, we cannot guarantee your embedded video will work.
• If your video is not embedded, most likely your video has not been copied/transferred correctly, so you have to check the time between the encoder and when the encoder finished and tried to copy it to the streamer.

• Check if the video is HTTP or HTTPS, if your site is HTTPS, your video must also be HTTPS, otherwise, the video will not work
• If you didn't use the encoder it's possible that your video doesn't have a codec compatible with your browser, the use of the encoder is highly recommended.
• Copy the URL of the video and paste it directly into your browser, and try to play directly to detect more errors.
• Check the network tab of your JS console