Thanks for reaching out to us in the land of the Forums. We do apologize that have lost your port settings. Most likely the easiest thing to fix this issue, is by actually starting fresh, just like you did when you first got your Slingbox.
The first thing we would recommend is that you actually reset the device. This needs to be done when certain changes have been made to your set up. In this case the router has been reset. Check out the article below that will show you how to do that. Once that is complete, then you will need to go to setup.slingbox.com and reconfigure everything. The setup should now recognize the router again, and automatically set it up for you. If not, we have also included a great article that will show you how to manually go in and configure your router.
Hope this helps!
The Slingbox Moderation Team