Hi Rajesh,
The failed queue name is "R3AD_BUPAxxxxxxxxxx".
So it seems the error occured while delta downloading ERP BP to CRM BP.
Error is "Partner xxxxxx does not exist".
Which means the ERP BP was not initialed in CRM side.
If your system scenario is "ERP BP -> CRM BP" replication,
Please request download the ERP BP to CRM system then try to process the inbound queue again.
BR
Dean Yan