sounds like you may have a clog in the nozzle or bowden tube. disconnect the tube from the extruder, preheat pla end option in the menu, then when at temp, disconnect the tube from the extruder and also remove the nozzle. Nozzles are cheap, so may as well replace that while it's out, but stick a pin through the bowden tube, if it gets stuck, it's clogged. if not clogged, you'll be fine with replacing the nozzle, if clogged, you may be able to get away with cutting the clogged portion off, or if too short, replace the tube. the tubing most are currently recommending is capricorn ptfe