Some customer numbers of ECC is not flowing into CRM through CRM-middleware.

Hi,

I have configured delta loading in R3AC1 for CUSTOMER_MAIN object with filter condition kna1-kunnar low = 050000000 and high = 0599999999 in  CRM7.0 system to transfer customer number (kna1-kunnar) from ECC system to CRM. some of customer numbers  are not flowing through middle ware.

There are no entries struck in queues and no error messages in smw01.

But whenever i reprocessed those particular customer numbers using R3AR2 & R3AR4 , those are flowing successfully.

Can anyone please tell me why those customer numbers are not flowing under delta loading process.,and  i am not getting to where those numbers are going , because there are no queues strucked and no error messages.