Thanks for asking! I understand you have replaced the router that was originally connected to your Slingbox when you initially set it up. In this case, the Slingbox was given an IP address from your old router and now needs a new IP address from your new router. To do this you would need to factory reset the Slingbox and reconfigure it at setup.slingbox.com.
Here is an article that will further assist you with factory resetting the Slingbox:
If you have any other questions, feel free to respond or give us a call at 1-877-467-5464. We are open seven days a week, from 10:00am to 10:00pm EST.
Hope this helps,
The Sling Media Moderation Team