It can be frustrating to discover your load damp and have to run it again. I think I might have some answers.
How wet are your clothes when you put them in the dryer? Your washer could be the problem! It may not spin the clothes dry enough, and you’re putting wet clothes in the dryer. Drying clothes will take much longer.
What length of time has your dryer vent been in use? How long have you had it inspected/cleaned? Your dryer vent may not be venting directly to an exterior wall. It should have elbows or vents to the roof. The dryer cannot move enough air through the vents to dry clothes.
When your vent becomes blocked, the lint can back up into the dryer cavity or, in certain models, the blower housing. This is a serious fire hazard. Your vent should be professionally cleaned and inspected every year. To properly clean your vent, you should not just bend a hanger around it once a year.
Check how wet your clothes are before you load them into your washer. Also, make sure to check the vent and vent material. Dryer problems may continue if you have any problems. Check to see if your dryer element is functioning properly, and if the control board keeps the temperature and dry times correct.