T4 line 16a - Entering any number results in a warning that the CPP/QPP has been entered incorrectly.

[jci]

If I enter any number through the forms interface for form T4 line 16a, the field for Employees Second CPP Contribution, Turbo Tax reports that I have entered the data incorrectly when I complete the review.  Am I doing something wrong?

CPP/QPP contributions or pensionable earnings have been entered incorrectly. Check the amounts entered on your T4; particularly boxes 10, 14, 16, 16A, 17, 17A, 26, and 28. If the information entered matches your slips, please contact TurboTax support at https://support.turbotax.intuit.ca/contact/

[TurboTaxSusan]

Please make sure that everything is filed out on your T4 slip ex: Box 10 (province), Box 26 (pensionable earnings)…