The IRS says I need to send in my 1095-A (I did not have marketplace coverage at all this year). I had employer health coverage and received a 1095-B. How do I prove I did not have that coverage?

Yes, this is an automated notice that is sent because the IRS received a copy of the Form 1095-A that shows advance payments of the premium tax credit were made to your or your family's health insurance company to reduce your premium costs.

However, if this is inaccurate, then you will need to contact the IRS at the number provided on your notice and explain the situation to provide proof of your insurance on Form 1095-B. 

See the following FAQ for more info on this notice. https://ttlc.intuit.com/replies/4508105