Deficit of SL Bl.stock returns in 453 mvt

Hi,

while transferring the material from returns to unrestriced via 453 Mvt ,the system shows the following error message

Deficit of SL Bl.stock returns 28 EA :material plant storage location

Message no. M7021

But i have cchecked the stok level in the returs type for that storage location .there is enough tock in the location then why sytem diply this error bcz i couldnt find the solution

Pls advise me how to reslove this error

Thanks in Advance

Regards,

Renuga.A