Why won't my duravent 6 in black pipe fit into the 6 in wall

Reviews for DuraVent PelletVent 3 in. x 6 in. Double-Wall Chimney

Why won't my duravent 6 in black pipe fit into the 6 in wall thimble? : r/Fireplaces

Wall thimble : r/woodstoving

6'' DVL Double-Wall Black Tee with Clean-Out Cap - 8655

How to connect 6in wood stove pipe to double pipe chimney?

DuraVent DuraPlus 24x6 inch Galvanized Steel Triple Wall Stove

Simpson Dura-Vent 6DVL-68TA Duravent Telescoping Connector Close

DuraVent DuraPlus 6 in. x 24 in. Triple-Wall Chimney Stove Pipe

IMPERIAL 24-in L x 6-in Dia Black Steel Stove Pipe in the Stove

ALLFUEL HST AllFuel 6 in. x 6 in. Single Wall 45-Degree Elbow

Duravent 6 Durablack Single Wall Stovepipe

US Stove from Tractor Supply : r/woodstoving

Is this an acceptable install? : r/woodstoving