Error in the Bank Reconciliation

Hi,

As per the attached Screen shots, We have already reconciled bank reconciliations upto 30th November 2023. when we try to reconcile the month of December 2023, The Bank Reconciliation shows the book balance of last reconciliation as zero. however, there was a book balance at the time when we posted the bank reconciliation as at 30th November 2023.

Could you please advise how to solve this?  

Thank You