Benjamin Disco .22 (Leak)

Good morning,

I haven't shot my disco in a few months and took it out of the gun case and still had a little air in it. When I pumped it to just over 1000psi I detached it and noticed it was leaking out of the fill port. After all the air leaked out I removed the fill port and figured it was dirty and cleaned it - removed the old plumbers tape and applied more. Same thing.

any thoughts on where I should start or can anybody point me in the right direction to purchase a new one? When I bought this last year from this forum (my first PCP) the seller mentioned he put a new one on it.

Thanks!