You either put it together wrong, which is easy to do, or you cut or misguided the seals when pushing it in.
At least you know it's the servo, lol, just remove it and start over.

I don't know all the names exactly to the servo, I just know how it goes in, but I do know that one part that looks like a crown, the crown points outward and the part immediately under the cover, the center part that is higher, points outward too.

hope this helps,
allen