Customer that has [Customer: (Blank)] does not exist errro for setup PO to CO Cross Site

Customer that has [Customer: (Blank)] does not exist errro for setup PO to CO Cross Site
if you are facing the problem when you click Cross site at the PO header .

Customer that has [Customer: (Blank)] does not exist

please check for replication rule and site

Site/Entry->Site User MAP -> put the user there