Common restriction points
Lint buildup, crushed transition duct, a stuck exterior flap, nest material and long runs with multiple bends can all reduce discharge.
Bird or pest evidence changes the service
Scratching, chirping, visible nesting or debris at the termination should be treated as a possible wildlife blockage rather than ordinary lint cleaning.
Repeated restriction may indicate a routing problem
If the same system clogs again quickly, the vent length, bends, concealed materials or damaged sections may need a structural review.
Service note: The assigned provider confirms the actual cause, access, scope, price and schedule before work begins.