Extenall call with transfer - called subscriber cannot hear voice

PBX-E1-Sangoma-FreePBX-SIP-Externall party . When PBX operator make external call an then transfer it to an analog subscriber —called party cannot hear voice . Internal PBX subscriber hear voice . If transfer is made to a digital subscriber call is perfect … If I take the freePBX out and put an old asterisk with sangoma E1 card everything is ok … please help