ERROR 2204: This callback ID is already registered in the delivery report
This error happens if the mobile operator returns the same callback reference
ID for two different messages. It can also happen if you send your messages
through a GSM phone or GSM modem and you send several messages to the same
phone number over time.
What is the callback reference ID
When the Ozeki software submits an SMS messages to the SMS service provider
(Mobile Network Operator), the SMS service provider returns a unique string.
This unique string is called the callback reference ID. The callback
reference ID is also included in delivery reports returned by
the SMS service provider. You receive a delivery report SMS message in case the
originally submitted SMS is delivered to the recipient handset.
How are callback reference ID's handled in the Ozeki SMS software
When an SMS message is submitted the callback reference ID is stored in the
Ozeki software for the purpose of matching future incoming delivery reports
to submitted SMS messages. When a delivery report SMS is received the Ozeki
software checks the callback reference ID included in the delivery report
SMS to find out which originally submitted message this delivery
report belongs to. If the originally submitted message is found it's status is
set to delivered and the callback reference ID is deleted from the Ozeki
When does Error 2204 happen?
Error 2204 happens if the SMS service provider fails to provide a unique
callback reference ID for each submitted message. In this case if an incoming
delivery report arrives, there is know way for the Ozeki software to decide
which originally submitted envelope it belongs to.
The error can typically happen if a GSM modem is used and several messages are
sent to the same phone number. If a message is submitted through a GSM phone or
GSM modem, the callback reference ID is made up of the last few digits of the
phone number and a number that iterates between 0 and 255.
When can I do about this?
Not much. Simply ignore it.
M - Country codes