There was a browser-specific bug (which seems to be affecting some, but not all, Chrome and Firefox users) in the plot's current dominos puzzle that kept solutions from being interpreted as correct. It has been fixed, but if you were affected you will need to refresh the puzzle page in order to submit your solution. Simply submitting the solution after the fix was pushed will not help, as the buggy code that interprets your answer was loaded when the page itself was loaded.
If you are still having any problems with a newly loaded page, please let us know!
At first it was only turning one direction. i kept trying once a hour to see if it would start working. around 10 or so it started flipping all the way around