Diagnosis
This is almost never the dryer's fault. It's a restricted exhaust vent. The moisture can't escape, so clothes bake instead of dry.
How to Fix It
Disconnect the flexible duct from the dryer and the wall. Clean both. Use a vent cleaning brush kit on the rigid wall vent all the way outside. The entire path must be clear.
If That Didn't Work
With the vent disconnected, run the dryer on a timed cycle. Feel for strong, hot airflow at the outlet. If it's weak, check the internal lint trap housing and blower wheel for a lint plug.
Heads Up
A clogged vent is a fire hazard. It also ruins the thermal fuse and overheats the heater assembly. Clean it first, before blaming internal parts.