In case that you still have issues to connect to the Slingbox using Watch at slingbox.com, we recommend trying a different Internet Browser; if you are using Safari, download Firefox to determine if the issue persists. You can also try to reset the plugin; have a look at this article:
On that link, you will find the instructions for Firefox, but you can try to Reset Safari to the default settings and try again to install the plugin.
Regards and hope this helps.
Thank you for participating in the Slingbox Answers Forum. I have attached a link below that I hope will be helpful in finding a resolution to your issue.
Hope this helps,
The Sling Moderation Team