Well you messed up ... you should have waited to file until the ITIN was renewed ...
The Protecting Americans from Tax Hikes or PATH Act made several changes to the tax law ...
http://www.thetaxadviser.com/newsletters/2016/jan/congress-makes-changes-to-popular-tax-credits.html
Retroactive claims: One change the legislation makes is to prohibit retroactive claims of the child tax credit. It does this by preventing taxpayers from amending a return (or filing an original return) to claim the credit for any prior year in which the taxpayer or the qualifying child did not have an individual taxpayer identification number (ITIN). This means that taxpayers cannot file returns claiming the credit using an ITIN issued after the year for which the credit is being claimed. The effective date of this provision allows taxpayers to file their 2015 returns without regard to this rule if the returns are timely filed (Section 205 of the Act).
