Connect a vacuum source to it and listen in the cabin with the filter out.
If it remains plugged you hear nothing. If you hear air flow, the hose is likely off.

Spidies do crazy things. Like nests in propane feed tube to my BBQ burner. It would light and shoot flames out near the dial. I took it apart and yep, habitat in the tube to the burner.

 

Picked up my car this afternoon.

Hose came off. Cost of the receipt was 130.00 dollars. But my car is still under warranty for another 2 years.

 

Another common blockage problem ( Other than a spider nest) IS
Algae and mold buildup in the evaporator pan . the Drain tube leads to this.