plant at item level of PO

Hi experts,

I am quite new in the area .I have now a problem with PO.

At the item level of my PO, the plant will not be extracted automatically. Is this normal?

And after I entered the plant manually and the error message shows up:

""the material xx not listed in plant".

I have checked the material master data and found this material has been extended for this plant.

How can I fix this problem?

Best regards,

Fan