Thanks for posting in the forums! I'm sorry to hear you are experiencing this issue. So if I understand your post correctly you are not able to consistently connect to your Slingbox? You stated that the IP address has a 3 day lease. Does this mean that it is constantly changing every three days? I would recommend trying out the following articles to attempt to resolve the issue:
Hope this helps!
The Sling Moderation Team
In answer to your question about the DHCP lease,
No the IP pool is only for 1 IP address but the 3 days is insignficant as after about 3 hours I am no longer able to connect to my sling box. I can only restore viewing capabilities after unplugging the power to the slingbox and then plugging it back in. I have spoken with tech support and they spoke of an issue with power supplies and suggested I buy a new one. I have done that and still continue to have the same problems.
I can put a computer in place of the sling box and access it consistently with rdp and or filezilla without loosing connection so I know UPnP is working. Therefore I must refer back to possible issues with the slingbox itself?