Unable to Correct PO matched Invoice

Hello:

When selecting Match or Correct Lines, and unchecking the exclude boxes, the search does not show any of the PO data. My search on the topic most often references an inactivated buyer. As far as we know, the buyer has not been deactivate and see other PO's by the buyer. What other reasons would cause this behavior? Thanks!

P.S. I am able to create a "new invoice" and when matching the PO, the info is presented; so what would be the reason it is not presenting in the old invoice?

Regards,

Shashank