Unable to bind port for usrp connection after adding 16 nodes

Hello,
I setup several private nodes and after 16 I get this error
[Sep 24 12:28:33] NOTICE[30064]: app_rpt.c:22228 rpt_master: RPT thread restarted on 1199
[Sep 24 12:28:33] WARNING[30064]: app_rpt.c:22240 rpt_master: rpt_thread restarted on node 1199
[Sep 24 12:28:33] WARNING[30134]: chan_usrp.c:278 usrp_alloc: Unable to bind port for usrp connection

I have tried several different ports for the usrp and it still gives me this error.
Is 16 the max nodes you can put on allstar with the USRP driver?

Thanks,
Mike (N0VZC)