It's such a pain when our projects have problems. It is going to be gorgeous. Let's look at a couple of options.
Re-check the blocks in the row that is off. Are they squared up to size? What about the sashing borders? Is each block of the twine border the correct size?
What is the measurement in the center of the quilt? How far off the measurements from center?
When you added the red sashing did you measure, pin across the edges? These borders can stretch the quilt edge. It might work to check that red sashing/border first, stay stitch it, re-pin and stitch back on.
It may involve from ripping and adjusting to get this one done.
PS: You may be able to adjust the twine border. Cut the strips just a little smaller in each one until you get the adjusted size you need.
Good luck and best wishes. You will get there!