It seems that you cannot get the remote connection to your Slingbox, although it seems to be working fine at home.
First, we recommend you to reset the Slingbox and run the Setup Assistant for Internet Viewing. The following link will provide you with the steps to follow:
Since you have not included any information about your router, we recommend you to use the Slingbox Network Setup Assistant to help configure your router:
During this process, you will be able to check and adjust all the settings in order to configure your Slingbox with your AV source. Make sure to check all the connections between the Slingbox and your set top box (if any).
If the audio issue persists, I recommend you to check the following link in order to fix the Slingbox audio issue:
Hope this helps!