Safari doesn't allow media to auto-play without user interaction first, ie "Turn music off/on", changing the board display, etc. Chrome has similar behavior if you load a draft and don't click or touch anything (song won't play). However, it will shake loose after you take any action on the screen:

  • Click the "Draft Options" drop-down icon, then turn the "Music" off and on again.

Next, check your music volume, and make sure it's not set to the lowest amount in the slider. 
This can be done opening the AUDIO menu, and making sure the slider isn't all the way to the left:



If you continue to have issues hearing music, there may be something in your browser cache blocking it.
To resolve this you will want to clear your browser cache:

  1. In your Chrome Browser, select "Chrome > Clear Browsing Data" from the Chrome Menu bar.
  2. Make sure to check "Site Settings" from the Advanced tab, and "Cookies and..." / "Cached images and files" from the Basic Tab. Then click the "Clear data" button.