Try moving the right sliding door to test if the motion is smooth all along.
If not, go back to STEP #04 and #05 to readjust the wheels and make sure that they nicely slide on the whole length of the structure.
Then, repeat the same steps with the front left door and the two other doors located at the back of the structure.
Verify the alignment of the left and right doors by looking at the magnet assemblies, as shown below. They should make good contact when the doors are closed and be vertically aligned.
