Maybe you are not screwing it on properly?
It’s really hard to imagine why the AirNav antenna wouldn’t be working while a paper clip is working.
Did you move the AirNav antenna?
In some cases interference can cause reception problems, but i don’t know.
If you want you can make a spectrum, once with the paperclip and then with the AirNav antenna: Do I Need A Filter?
The only other possibility i can think of is that that the AirNav antenna coax that came with it has a fault from being curled up too tightly.
A break in the coax could cause total loss of signal.