When I print a long label or many labels continuously, printing stops suddenly before finishing.
As the printer uses direct thermal (heat) technology, the inside of the machine can become too hot to print. When the temperature gets too high, the machine pauses printing to give the machine a chance to cool down.
While paused, the LED is red solid and "Over Heat" appears on the LCD (for LCD compatible models).
Once the temperature has dropped sufficiently, printing will resume automatically.
Do not turn off the printer while it is cooling, otherwise the print job will be deleted.