Thank you for posting in the Sling Media Answers Forum! I'm sorry to hear you are having issues connecting to your Slingbox 500.
It sounds like the Slingbox did not recover after an automatic update. I would recommend resetting the Slingbox to factory settings. After you do this, your TV will prompt you to run through the setup again. After this is done, you should no longer experience any issue.
Below is a link to an article from our support site that explains how to reset your Slingbox to factory settings:
Hope this helps!
The Sling Moderation Team