Unable to process invoice due to Transaction Type Error

Hello Sapians,

I have a scenario where, GR was done for P.O's in 2015 but now they want to post the Invoice (MIRO) in 2016.

These P.O Acct *** Cat is set to "A". However, the process hit a snag as the system is issuing the below error.

Already searched SCN and SAP Service Market place for help in vain.

Any inputs to resolve the issue will be appreciated greatly.

Regards,

Sudhakar*