What is meant by "Fixed Date Conformity" on Virginia form ADJ/CG?

Not all states conform to the changes in the federal tax laws. 

Fixed date conformity means that a state conforms to the federal tax code as it existed on a certain date. The current conformity date for Virginia is February 9, 2018.  This means that the state does not automatically incorporate changes to federal tax law that occur after that date.

 I HAVE AN ERROR MESSAGE ON THIS STATE RETURN, SAYS IT CANNOT BE FILED.  ANY THOUGHTS ON HOW TO FIX IT

check availability. only state forms that have been finalized can be e-filed. By the way, there's no rush. The IRS will not open e-filing until 1/27/2025. Until then any submission will sit on Turbotax servers.  The federal 1040 must be accepted and the state forms must be final. Until then any attempt to e-file the state should be rejected.