If for any reason your records have a discrepancy and are not balancing the first thing you should always check is your Opening and Closing balances making sure both are correct.
If you need to try and start your reconciliation from the beginning press the [Cancel] button on the bottom left hand corner of your screen.
Click on [Reset] which is next to the [Cancel] option on the bottom left hand corner of this screen. This un-ticks all transactions again and allows you to step through Reconciliation process again.
Always also check all transactions have only been entered in once and ALL transactions areentered correctly.
Also check your closing balance from previous month is correct in settings area.
Check your closing balance for month you are working on.