DLR error in Opensmmpbox kannel gateway

I have configured my servers to send from ESME to SMSC through OpenSMPPBox,
i have applied the below flow
ESME -->> OpenSMPPBox -->> SQLBox -->>Bearerbox -->> SMSC
I have succeeded in sending the sms from ESME to the SMSC but my problem is
related to the DLR.
The Bearerbox actually received the DLR from the SMSC but it didn't route
it to the ESME.

What is the required configurations that could resolve the above issue. i
need to route the DLR to the ESME

Your help in this regard is highly appreciated and thanks in advance.i can see entries in db when i send msg

Below are my config files and log error,
2022-05-07 14:36:47 [3023] [7] DEBUG: DLR[mysql]: Looking for DLR smsc=smpp1, ts=1a11039a-901d-43e3-8f99-1b42fa14aacb, dst=+260976198318, type=1
2022-05-07 14:36:47 [3023] [7] DEBUG: sql: SELECT `mask`, `service`, `url`, `source`, `destination`, `boxcid` FROM `dlr` WHERE `smsc`=? AND `ts`=? LIMIT 1
2022-05-07 14:36:47 [3023] [7] DEBUG: column=mask buffer_type=253 max_length=0 length=4
2022-05-07 14:36:47 [3023] [7] DEBUG: column=service buffer_type=253 max_length=0 length=16
2022-05-07 14:36:47 [3023] [7] DEBUG: column=url buffer_type=253 max_length=0 length=2048
2022-05-07 14:36:47 [3023] [7] DEBUG: column=source buffer_type=253 max_length=0 length=32
2022-05-07 14:36:47 [3023] [7] DEBUG: column=destination buffer_type=253 max_length=0 length=32
2022-05-07 14:36:47 [3023] [7] DEBUG: column=boxcid buffer_type=253 max_length=0 length=16
2022-05-07 14:36:47 [3023] [7] WARNING: DLR[mysql]: DLR from SMSC<smpp1> for DST<+260976198318> not found.
2022-05-07 14:36:47 [3023] [7] WARNING: msg_to_pdu failed, sending negative ack