Dryer lost heat - Dryers

This may be a heating element issue.
If you want to do a few things before calling someone, you would want to start by making sure all of your dryer settings are set correctly. Some dryers have "air" settings or "delicates" settings. These settings are going to be very low heat so the clothes are not ruined.

Also make sure that the lint screen has been cleaned each and every time you have started a new load. If not, you can UNPLUG the dryer, pull the dryer out and with some simple tools, take the back off and vacuum what you can get to. If it's very dirty you'll want to call a professional. You'll need it cleaned and your problem diagnosed. If cleaning the lint screen is not something you have done on a regular basis, then please start. This could be a fire hazard if it is not cleaned regularly.

Another thing to check is your vent or vent hose. Depending on how your set up is, if your hose is crimped behind the dryer and the heat can't escape, the clothes will not be able to dry. This would only be something if you have some heat but clothes are not drying. Also, sometimes due to the age of the hose, previous use, not cleaning the lint screen, etc, the venting from the house to the outside could be clogged. Again, there will be some heat, but the clothes will seem to take forever to dry.

Good luck.