Dunning Block

Hi

I am getting a error ........

Adfvacne payment is made............This is very old advance payment....two years back

Now When we are trying to clear Advance payment it is giving an error.....advance payment document is having a dunning block.

We are not able to remove dunning block and we dont know whether error is bcox dunning block in advance payment

now to pay clear this.....please advise.

Thanks