kannel smpp: unable to get the acknowledgment - sms

Question

I'm working on a project for sending SMS using SMPP protocol and KANNEL.
Everything is working well; the only problem is that I'm still unable to get the acknowledgment, so I can't know if the message was successfully received by the client or if I should send it again.
Please, does anyone have an idea on how I can solve that? Or if there is a tool with a UI that I can use instead of KANNEL?
Here is my config file:
group = core
dlr-storage = internal
admin-port = 13000
admin-password = password
status-password = password
admin-allow-ip = ''
smsbox-port = 13001
log-level = 0
log-file = "/usr/local/kannel/logs/kannel.log"
box-allow-ip = "127.0.0.1"
group = smsbox
smsbox-id = BOX1
bearerbox-host = 127.0.0.1
sendsms-port = 13013
log-file = "usr/local/kannel/logs/smsbox.log"
log-level = 0
access-log = "usr/local/kannel/logs/access.log"
group = sendsms-user
username = user
password = password
group = smsc
smsc = smpp
smsc-id = SMSC1
host = my_host_ip
port = my_host_port
smsc-username = user
smsc-password = password
address-range = ""
system-type = ""
transceiver-mode = true

Answer 1

When sending your message, make sure you have your registered_delivery flag set appropriately.
Add dlr-mask = 31 to "group = sendsms-user"
OR
Using the Kannel HTTP API, set your dlr-mask. For example:
http://localhost:13013/cgi-bin/sendsms?username=tester&password=foobar&to=[phone]&text=Test&dlr-mask=31
From the Kannel User Guide: "dlr-mask: Optional. Request for delivery reports with the state of the sent message. The value is a bit mask composed of: 1: Delivered to phone, 2: Non-Delivered to Phone, 4: Queued on SMSC, 8: Delivered to SMSC, 16: Non-Delivered to SMSC. Must set dlr-url on sendsms-user group or use the dlr-url CGI variable."