Please double check your T4 slip and make sure all the amounts are correct & in the right boxes. Also make sure that you have not indicated that you are exempt from CPP in box 28 at the bottom of the T4 slip page. You can get back to the T4 page by using the Find tool in the top right to search for T4. Select it from the list and then click Go.
If you are still unable to resolve this issue, please contact our phone support as they will be better able to assist you. You can get the correct number by using this form: https://support.turbotax.intuit.ca/contact/