DLRs getting deleted from Msql

I have kannel v1.4.4 running properly am able to sending messages and
receive dlrs as per access log.

but I cant see it getting saved to msql as table dlr in temp_dlr is empty.
I have checked bearerbox.log and am getting below action that dlr is
getting deleted. How do I resolve this?

Bearerbox.log below
………………………………………………………………….
removing DLR from database
2018-12-11 14:34:08 [16289] [7] DEBUG: sql: DELETE FROM `dlr` WHERE
`smsc`=? AND `ts`=?  LIMIT 1

………………………………………………………………………

Thanks in advance
Chris