Hello, I understand the T38 behavior changed after 1.6.13. I watched Brian's video from last year, read the docs, but I just don't see what else I would need for a very simple scenario for receiving a fax with the receiving end (ATA) re-inviting T38. PSTN > FS > HT801 ATA > T38 RE-INVITE > FS > PSTN The ATA does re-invite, however FS rejects immediately with 488 Not Acceptable Here. I'm using the following dialplan. I also tried to use export instead of set, but same result. <extension name="faxdid1" continue="false"> <condition field="destination_number" expression="^(4154447777)$"> <action application="set" data="ignore_early_media=true"/> <action application="set" data="fax_enable_t38_request=true"/> <action application="set" data="fax_enable_t38=true"/> <action application="bridge" data="user/6050@sip.domain.org"/> </condition> </extension> Is there anything obvious that I'm missing here? FreeSWITCH (Version 1.6.20 -37-987c9b9 64bit) Thanks Mike