Freeswitch and SPANDSP reinvite to T38 is not accepted

FreeSWITCH Configuration
1

Hi,
i have FreeSWITCH version: 1.10.9-release-21-a615e85afc~64bit (-release-21-a615e85afc 64bit) with spandsp running.
If I recive a incoming fax and the caller sends the reinvite to t38 freeswitch refuse always the switch:

023-06-29 08:11:31.686980 97.53% [DEBUG] sofia.c:7487 Channel sofia/external/xxx@sip.demo.eu entering state [received][100]
2023-06-29 08:11:31.686980 97.53% [DEBUG] sofia.c:7497 Remote SDP:
v=0
o=anonymous 168801908723 168801908724 IN IP4 92.243.xxx.xxx
s=SIP Call
c=IN IP4 92.243.yyy.yyy
t=0 0
m=image 34834 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:9600
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:1000
a=T38FaxMaxDatagram:200
a=T38FaxUdpEC:t38UDPRedundancy

2023-06-29 08:11:31.686980 97.53% [DEBUG] switch_core_media.c:5118 sofia/external/xxx@sip.demo.eu T38 ACCEPT on request
2023-06-29 08:11:33.766956 97.53% [DEBUG] switch_core_media.c:5222 sofia/external/xxx@sip.demo.eu T38 IS NOT POSSIBLE on request
2023-06-29 08:11:33.766956 97.53% [DEBUG] sofia.c:8450 Reinvite resulted in codec negotiation failure.

my dialplan contains the following settings:

     <action application="set" data="absolute_codec_string='PCMA'"/>
     <action application="set" data="t38_passthru=false"/>
     <action application="set" data="zrtp_secure_media=false"/>
     <action application="set" data="fax_enable_t38=true"/>
     <action application="set" data="fax_enable_t38_request=true"/>
     <action application="set" data="fax_use_ecm=off"/>
     <action application="set" data="ignore_early_media=true"/>

Has someone a hint for me to resolve this issue?

2

Do you wanna pass reinvite to other side or do interworking ( t38/audio)?

3

What is the sending party codec? Might be other than PCMA