Not hearing sounds with Chrome/Firefox notifications

Our desktop app running in Chrome/Firefox/Safari plays sounds when presenting notifications.  If you do not hear sounds when receiving popup/desktop notifications, first make sure the sound icon is enabled:

If it's greyed out, click it to enable sounds.  Next, ensure that the browser has allowed the client.pushover.net site to auto-play sounds.  In Chrome and Firefox, click the icon to the left of the URL bar and you should see site-specific settings:

If you do not see a setting for Sound, click Site settings and then change Sound to Allow.  You may then be asked to reload the page for these settings to take effect.