I have a SlingBox Solo sitting behind an AT&T DSL 2WIRE router. It works fine over my home network, from my office, from Costa Rica (Slingbox tech) and from a couple of other locations. However, it does not work when my daughter tries to connect through her FIOS link in her apartment. It successfully connects, but then sits in the optimizing phase for a couple of minutes w/o every displaying any video/audio. The connection then drops.
Message was edited by: sjjs I've also tried switching from port 5001 to port 443 and then port 80. It still failed to stream at my daughter's apartment. It continued to work just fine from my office location with both alternate port configurations.
Turns out it was an mtu issue caused by the combination of the 2WIRE router, the FIOS router and the sling box. For some reason, the end to end mtu size negotiation wasn't taking place correctly. A sling box tech was able to remotely force the mtu size the slingbox solo was using to 1452 bytes. The player is now able to stream properly at the problematic location.