The error message is "The document has the wrong tax year or some other issue that prevents us from opening it. Please make sure you have the right file and try again."

I created 3 files on my MacBook with Turbotax Home & Business 2018, one for me and one for each of my sons.  I can open their files no problem.  Mine, on the other hand, is giving me this error message.  I was nearly done with the return so I hope all that work isn't lost.  Please advise.