The dryer is rocking, the discharge is plugged or restricted, or the hose is bad. So...
Check that the dryer is setting on all 4 feet, and is level front to back and side to side.
Remove any lint from the dryer to the point of dischage.
Inspect the flapper at the discharge to ensure that it is free.
Now, as for the hose, if it is a vinyl one, throw it away and replace it. There are hoses available, but I always use rigid 4" metal duct and elbows, with foil tape, and have not encountered any installations in which it was necessary to use anything less. All you will need is a pair of tin snips to cut the duct to lenght. Do not screw joints together, as they will collect and hold lint.