PL Val. GR Blkd St. exceeded

Hi,

I am having a PO with origin acceptance and order quantity as 60 MT. I have raised a GRN with movement type 107 for 60 MT. Upon the physical receipt of a material 2 GRN raised with movement type 109 for the quantity 20 MT each. Now I am trying to receive balance 20 MT with movement type 109 system is showing the error message "PL Val. GR Blkd St. exceeded by 3.000 KG : Material Plant Location Batch". Can somebody help me on this issue.

Abhishek