It's most likely that your mouthpiece needs to be cleaned. If you look at the bottom of your mouthpiece, you'll see a metal piece at the end of the spring. This is the filter section and it might have been clogged. Clean as needed.
Also check and make sure your fingers don't cover the air holes on...
Convection heating uses the airflow from you pulling on the device to circulate hot air inside the chamber. When hot air is passed through and around the herb, the terpenes and cannabinoids boil off at their ideal temperatures. This means dry herb is not directly touching the heating element. Make sure to take slow steady draws....
