I like when the squirrels move in.
First.........unplug dryer.
Then...
You need to clean the vent entirely..not just at the connection. Clean it all out and you can sometimes remove the back panel of the dryer and find tons more dryer lint.
By the way ..dryer lint is the key ingredient in fires.
It is in the top ten house fire starters...clean em out bi-monthly at least.