Sometimes the last stage of the laser focus system becomes misaligned. This is usually due to vibrations from use over time.
Some steps require careful timing. Please read carefully all the way through before attempting this feat.
Put in a piece of scrap wood
Adjust the height of the nozzle using the acrylic key hanging inside the main door. return the key.
In the Redsail app start a new design. Draw a single horizontal line moving from left to right. Set the speed to 3.
Download the design and start.
Open the laser cutter door a fraction. The beam will turn off and the machine will stop moving.
Open it even further and, without moving the scrap, observe the difference between the red laser dot and the beam cut.
Loosen the bottom screw and adjust the nozzle until the red dot is just inside the right-most end of the cut. Tighten the screw.
Close the door for a moment and open it again. Note the change. Repeat if necessary.
Your cuts should now be back to tip-top shape.
More complicated alignments involve high voltage and should not be attempted without advanced laser training.