Blind Transfer fails from inbound PSTN call

[ihall]

I have 9 SPA504G phones. All of them can receive blind transfers except 1 from our Patten PSTN gateway. If any other phone does a blind transfer to this phone it fails with the following in the logs.
Leg L:2418.4[Extn] is terminated: Cause: 406 Not Acceptable/INVITE from 192.168.XXX.XXX:5060
L:2418.1[Line:XXXX<<anonymous] failed to reach Extn:XXXX, reason Not Acceptable HereReason Unknown

The configs and firmware for all the phones appear to be the same. Any thoughts? Thanks in advance!

 

[NikosT_3CX]

Hi,

can you please clarify what device is on ip address 192.168.XXX.XXX and sends the 406 message ?
On the other tab of the extension on the Management Console and also on the Advanced settings of the gateway on the Management Console, options Replaces and Re-Invite are enabled ?