I have the exact same issue.
I can stay connected from my laptop from my friends house. From my laptop at my parents house. From my work internet. From the internet at school. Basically absolutely everywhere but at my satellite apartment.
Clearly the slingbox and my at home network settings are fine. Clearly my laptop is fine since it gets it everywhere else. So it must be something in my network at my apartment. At this point I am leaning towards the cable modem itself. since if I bypass the router and go straight to it I still experience the "stuck at optimizing" after 3-5 minutes.
I have no idea what it could be though, I can stream hulu/netflix/ etc all at 3 megs plus. It is making me crazy.
What I understand from your post, is that you're having problems with the Slingbox streaming.
In this case, besides discard any streaming restriction preventing the Slingbox to work and make sure about hardwired connections at the Slingbox location, I would recommend to check the following links.
Mine is doing the same thing.
I think its slingbox.
But as seen be above Slingbox isn't taking fault for this.
nothing in my house, Network, connectivity, devices, has changed. but i guess i am supposed to troubleshoot my equipment.
All problems started occuring after update from slingbox. ????????
And my system is the problem ????
* Edited to observe Slingbox Answers Forum House Rules by Moderator. *