The troubleshooting ideas listed seem like they would only work for players whose games still show the expansion plot as possible to expand to. Those of us who gave all the materials and then lost the ability to expand that plot (no big green check mark, trees all gray/blued out, no expansion sign, etc,) are getting nowhere with the troubleshooting. Mine happened Sunday morning (plot B9) and I've force closed maybe 2 dozen times since then, powered down and restarted my phone twice, and visited multiple neighbors. Nothing. That plot cannot be expanded to. It does not seem to be a sync error, other than it was a rogue sync that caused it. I'll be patient and wait for a fix from S8, though I certainly won't be holding my breath.