The Check Lint Screen light is flashing, I've checked and the lint screen is clean! What's wrong?

The lights on the panel are all flashing. The check lint screen light is flashing. I've cleaned the lint screen and I've run a dryer vent brush through the machine and through the dryer vent to the outside. Everything is clean. Is there any type of switch or connector that might be dirty that is telling the dryer to check the lint screen?