Floor nozzle hose detaches

I have the Shark NV370 and I had to take the floor nozzle cover off to get to the Beater brush because something was lodged in there. So I took it apart, cleaned it all out and put it back together with no problem and IT WORKS!! My problem is the floor nozzle hose detached from the floor nozzle during the cleaning process & it went back on just fine but when I turn or swivel the vacuum it comes loose from the bottom! Any suggestions on why it won't stay attached and how I can fix it? The hose is secure in the fittings.