"Sender partner does not match with PO vendor" - Invoice IDoc posting issue

Hi SNC Experts,

We are currently trying to implement invoice collaboration feature in SNC->PI->ECC. But after we successfully created an invoice in SNC and receives an invoice idoc in ECC, we are getting this idoc posting issues(ECC) having "Sender partner does not match with PO vendor" error found in the idoc logs.

Any suggestions/tips in fixing the specified issue above?

Thanks!

-Walter Rogando