Inconsistent behavior with Siproxd

[dbg008]

Hi,
I am running PFSense 2.1.2 with Siproxd 0.9 on a Soekris net6501 and have inconsistent results making outbound calls.
I am using this for sip video calls outbound with a Lifesize passport.
I can consistently make calls to Zoom.us, Bluejeans, and sip5060.net test sites.
Lifesize has a a test site which I can complete calls to sometimes but not others. I need to get a call to their site in order to troubleshoot another problem.
Siproxd is configured to with lan = em1 and outside = em2 (which is correct) the rest is default as I am not permitting any inbound calls.

The logs report nothing, the outbound call shows up as busy, but I can call from other locations.
Any suggestions or ideas to try?
thanks Dan