Failing to send with UDPSocket

[OffByNone]

Hello everyone,

I am working on an extension to interact with local UPnP servers.  What I am trying to do is to send out a message on 239.255.255.250 looking for devices on the local network.  Currently my code will work for any IP other than 239.255.255.250, when I try to send there it appears to work but nothing goes out (I get no errors in the code and have inspected in both wireshark and Microsoft Message Analyzer to confirm nothing is getting sent).  I know that it isn't my computer as I can send out messages from other applications to that IP.  I have tried latest Nightly as well as Dev Edition and Stable.  I have also tried on three different machines two of which are win 8.1x64 the third is Ubuntu.

I did briefly get it working on Friday night and early Saturday.  But once I thought I had all the dependent bugs worked out it stopped working.  When it was working it was repeatable and worked probably more than 20 times in a row.  Early Saturday it started to intermittently fail and at one point it stopped all together and I have not gotten it to work since (tried many many times, on different sending and receiving ports, rebooted machines, tried different machines, different versions of Firefox, different OSes). 

I am not sure why I cannot send to this specific IP and would love some help troubleshooting as I am running out of hairs left to pull.

Any help would be much appreciated.

Thanks!