Yes, this is an IRS reject code. With this reject code, you will need to mail in a paper return for this year. You can contact your employer to see if they had another EIN that they used during the 2016 tax year that should have been on the W-2, but if not, you will have to mail your return.
Please see the following FAQ article to print and mail your return. https://ttlc.intuit.com/replies/3401713
