The red light is an indication that Rollo has a problem with your label.
Most likely, Rollo needs to re-learn your label.
Please ensure there are multiple labels available to Rollo and then run the automatic label identification. Simply press and hold the top circular button on Rollo until you hear one beep. Rollo will then move the labels back and forth to learn the gap and other label properties.
To watch this in a video, please see: Setup Rollo for First Use
If the automatic label identification does not work or the red light remains, please turn off Rollo using the power switch on the back and then turn the unit back on.