How to tighten/fix ice-maker's drainage tube connector?
We know them as "John Guest" (The Brand Name) fittings and they are prone to leaking as its only an o-ring sealing the fitting to the pipe, if the pipe has a scratch on it or isn't fully inserted it can leak.

They also can be fitted with a collar clamp that holds the release mech ( the red part in this fitting) from accidentally being pushed down and releasing the pipe from the fitting.



You can also get brass fitting for use with "John Guest" pipe, you can see them at the offical website.