Hi there, rrudden.
It may be that, since the mobile SlingPlayer uses less bandwidth than the Web version, your connection speed is sufficient for one and not the other. You mentioned that your Internet speed is fast; do you know, specifically, the upload and download speed at both the Slingbox location and your current location? Here are some resources to facilitate your investigation:
The Slingbox Answers Forum Moderation Team
The question was originally posted by my roommate but I realized that the problem was the bitrate last night but it is a very strange issue. I am able to get a picture again as long as I do not use the "Best/HD" setting on the web player. I am now never able to get the same speed connection to Slingplayer that I was previously able to after having an account since 2010 if I use that setting. If quality is set to Best/HD, bitrate seems to average around 100 kbps or less. If I set the quality to "Best" I can get a bitrate of up to 8000kbps and suddenly I have a picture. If I change it back to "Best/HD" I immediately lose my picture and bitrate once again falls to 100kbps.
My Internet speed at the house where the slingbox is and the house where I am trying to watch are both the same service provider and settings (Verizon Fios 50/25). I can transfer files between these two houses at speeds that far exceed the bitrate that the web player are reporting. Speedtest confirms speed as well.