My thought is that others may have run into this and have some pointers to share. I have Freeswitch 4.2.5 Branch 4.2 Switch 1.6.20 64 bit on Linux FusionPBX 3.16.0-11-amd64 #1 SMP Debian 3.16.84-1 (2020-06-09) x86_64 GNU/Linux. I'm using default settings as far as I know/recall. Obviously something must not be as it should be. My phones are a Polycom 650 and a Yealink T48G. My external test phone is a cell phone. It had only been used with a single extension for years until now when I added a second phone and extension. Before today I had noticed that hold was not working properly but did not use it. Attempting to transfer external calls between the two fails in the middle of the transfer. I press the transfer button and type the extension and then hit send but the call does not arrive and the call is hung up on the internal side but the external party does not know until something times out. If I put a call on hold it may be lost as well. Brief holds work. If I call out and then try to transfer that call the same thing happens. If I conference the other extension on an inbound call the external party is not getting any audio once the conference is initiated. If I then hangup on one extension the other is not aware that the call is over. The same is true for the external party. I can call the other extension and answer, when I hang up on either one the other does not know it's gone. It does not matter which phone originates or receives. At least audio works well. :) I've placed a FS log file here: https://drive.google.com/file/d/1VdoLqoPhr5mUE1ky1i2SJjXFChp9w-nM/view?usp=s... The call duration is 2 minutes from 9:30 to 9:32. IP's and phone numbers have been replaced and placed within < > brackets. Internal IP's retains the last 8-bit number. --- fs