I think it is self explanatory ... review your payments made and the entries on the tax return and see if they are correct.
Understanding your CP25 Notice
We made changes to your return because we found a difference between the amount of estimated tax payments on your tax return and the amount we posted to your account. You're not due a refund nor do you owe an additional amount because of our changes. Your account balance is zero
https://www.irs.gov/Individuals/Understanding-your-CP25-Notice
