setting send-connect-ack to true as below solved my problem:

<configuration name="freetdm.conf" description="Freetdm Configuration">
  <settings>
    <param name="debug" value="0"/>
    <!--<param name="hold-music" value="$${moh_uri}"/>-->
    <!--<param name="enable-analog-option" value="call-swap"/>-->
    <!--<param name="enable-analog-option" value="3-way"/>-->
  </settings>
  <config_profiles>
    <profile name="my_pri_te_1">
      <param name="switchtype" value="euroisdn"/>
      <param name="interface" value="pri_cpe"/>
    </profile>
  </config_profiles>
  <sangoma_pri_spans>
    <span name="wp1" cfgprofile="my_pri_te_1">
      <param name="dialplan" value="XML"/>
      <param name="context" value="public"/>
  <param name="send-connect-ack" value="true"/>   
  <!--param name="tei" value="<*0..127>"/-->
      <!--param name="overlap" value="<yes|*no>"/-->      
      <!--param name="setup arbitration" value="<yes|*no>"/-->
      <!--param name="facility" value="<yes|*no>"/-->
      <!--param name="facility-timeout" value="0"/-->
      <!--param name="outbound-called-ton" value="<*unknown|international|national|network-specific|subscriber-number|abbreviated-number|reserved>"/-->
      <param name="outbound-called-npi" value="private"/>
      <!--param name="outbound-calling-ton" value="<*unknown|international|national|network-specific|subscriber-number|abbreviated-number|reserved>"/-->
      <param name="outbound-calling-npi" value="private"/>
      <!--param name="outbound-rdnis-ton" value="<*unknown|international|national|network-specific|subscriber-number|abbreviated-number|reserved>"/-->
      <param name="outbound-rdnis-npi" value="private"/>
      <!--param name="outbound-bearer_cap" value="<*speech|unrestricted-digital|3.1Khz>"/-->
      <!--param name="outbound-bearer_layer1" value="<v110|ulaw|alaw>"/-->      
    </span>
    <span name="wp2" cfgprofile="my_pri_te_1">
      <param name="dialplan" value="XML"/>
      <param name="context" value="public"/>
    </span>
  </sangoma_pri_spans>
  <analog_spans>
</analog_spans>
</configuration>

On Wed, May 30, 2018 at 1:11 PM, Babak Yakhchali <babak.freeswitch@gmail.com> wrote:
Hi
I connected freeswitch to tda600 using a pri line and mod_freetdm. incomming calls from tda600 work without any problems but outgoing calls to tda600 drop with cause 102 after a few seconds after answering.
I pasted the logs from console on pastebin:
https://pastebin.freeswitch.org/view/5da22227