Bank reconciliation

Hi,

I am trying to reconcile my month of January.  However its showing an out of balance from my December but my December reconcilation is spot, there are no out of transactions showing and the calculated closing balance matches my bank statement balance which I input at the top but its not saving or reconciling.  I undid all of my reconciliations from July to December, and did them all again and they all balanced. Then went to January and all the reconicilations that I'd just done were out of balance again. The calculated closing balances from July - Dec 23 are exactly what is in my accounts on myob and on my statements.  I can't reconcile my January becuase of this. Please help