Problem sending faxes with hylafax/Iaxmodem: no carrier

I configured the modem, I can receive fax but not send.
If I configure the modem into config.ttyI11 file and put this string for calling: ATX3DT019xxxxxx\r]
it says: No local dialtone

so I modified a little bit in AT,X0DT019xxxxxx\r
and now says No carrier detected:

dic 21 13:32:16.26: [ 9609]: SESSION BEGIN 000000037 3919xxxxxxx
dic 21 13:32:16.26: [ 9609]: HylaFAX ™ Version 6.0.6
dic 21 13:32:16.26: [ 9609]: SEND FAX: JOB 24 DEST 019xxxxx COMMID 000000037 DEVICE ‘/dev/ttyI11’ FROM 'root <root@192.168$
dic 21 13:32:16.26: [ 9609]: <-- [14:AT+FCLASS=1.0\r]
dic 21 13:32:16.26: [ 9609]: --> [2:OK]
dic 21 13:32:16.26: [ 9609]: DIAL 019xxxxxx
dic 21 13:32:16.26: [ 9609]: <-- [18:AT,X0DT019xxxxx\r]
dic 21 13:32:16.26: [ 9609]: --> [2:OK]
dic 21 13:32:16.26: [ 9609]: SEND FAILED: JOB 24 DEST 019xxxx ERR [2] No carrier detected
dic 21 13:32:17.26: [ 9609]: <-- [5:ATH0\r]
dic 21 13:32:17.27: [ 9609]: --> [2:OK]
dic 21 13:32:17.27: [ 9609]: SESSION END

What could be the problem?
Thanks