DIAGNOSIS The label roll is misaligned or the paper sensor is blocked. The red light means it doesn't detect paper correctly.
FIX Re-seat the label roll perfectly. 1. Open the lid and remove the roll. 2. Check for any torn label debris inside. 3. Re-insert the roll, making sure it spins freely and the label edge feeds under the metal guide, not over it. 4. Close the lid firmly until it clicks. The printer should auto-feed a label. If not, press the feed button once.
IF THAT DIDN'T WORK The optical paper sensor (a small eye inside near the roll) is dirty. Power off the printer, use a can of compressed air to blow into the label compartment, focusing near the roll spindle. Re-insert the label roll and power on.
HEADS UP That grinding noise is the feed mechanism stripping the label backing. If you ignore it, you'll wear out the gears. Always stop and re-align the roll at the first sign of a feed issue.