I have bought a ceiling light second hand but cannot work out how to wire it in order for it to work properly. The fitting has three lights and each on has a live and neutral wire which all convert into two contacts (see pic). There is a single live and single neutral wire coming from the ceiling.

I initially connected one of the points on the fitting to the live ceiling wire and the other to the neutral wire but only two of the bulbs worked. When I swapped then around, a different bulb stopped working. Any help would be appreciated!

Bulbs not seated correctly, or lamp holders/bulbs faulty.