A transaction isn't reflected in the balance of your account
If you entered a transaction but your account balance is unchanged, you may have entered equal debit and credit amounts to the same account by mistake. The effect of such a transaction would take money from the account, then put it right back, causing no change to the account's balance.
Locate the transaction in the Find Transactions window. The transaction will appear in the Find Transactions window twice, once as a debit and once as a credit. Click the zoom arrow that appears to the left of the transaction (you can click the arrow next to either part of the transaction); the transaction will appear in the Record Journal Entry window as you originally entered it. Depending upon how your preferences have been set, you can either edit the incorrect account or reverse the transaction and reenter it with the correct account. (Choosing changeable or unchangeable transactions)