full disclosure here. you may be looking at a product that is similar looking but fundamentally different than what i think it is.
what you are looking at is a bulkhead light for furniture only. meant to be used inside a cabinet box or some other structure that is classed in the NBC as "furniture". even though many places sell these, you cannot legally use these for potlighting where they are submerged into a drywall ceiling, even I have seen these installed so many times in the wrong way. its disturbing. you cannot just cut a hole and clip these into the hole. I have worked on multiple different residences where these have caught fire outright or been smouldering when they were turned off finally.
1) there is no way to connect to the unit in a way that makes the connection compliant with the OEC. the connections have to be in a metal enclosure, and these don't come with it. I have seen every type of disturbingly mis-thought arrangement with these things.
2) the fire code requires that any penetration into the rooms fire barrier (the drywall ceiling) must be in an appropriately fire rated enclosure. since these have a power supply board either onboard or in a little separate module (with a molex connector usually), that part also has to be installed in an approved enclosure.
3) even if you want to do all your connections in an approved rework pot or some other device, they are a weird diameter that doesn't match any pots that I have ever seen.
4) ESA will not pass these in any installation I have ever seen, and I have had inspectors tell me that ESA is still working on getting the legislative clout to have them banned outright, so that they can't be sold at all in Canada without the aforementioned warnings. just remember that you can run electrical cable through a drain line, but its not legal. caveat emptor.
do yourself a favour and get led refit assemblies from cree or greenlite. I buy them by the skid from greenlite for about $15 ea. they are not that much more if you buy just a case of them. they have a 5 year warranty, honoured by a Canadian company, and they are bombproof, commercial grade lights.
http://www.greenlite.ca/en/lights/1895-led-10w-dimmable-retrofit-kit-4-.html
My bet is that the middle contact isn't sprung enough to be consistent.
First, turn the breaker off.
Then, gently tug at the central contact in the middle of the light fixture's socket to bend it a tiny bit further forward. Needlenose pliers can work well for this.
Don't bend it too hard; otherwise you'll have a broken light fixture to deal with.
Best Answer
The question is if the can has a built-in ballast for the florescent light. If the can uses standard screw-in CFL bulbs, then you can just replace the bulb (and probably the trim ring) with a retrofit LED module designed for use in a incandescent can.
On the other hand, if the florescent light has two or four pins to connect into the can, then the can is designed specifically for florescent and includes the ballast for the florescent light. In this case, you will need to replace the can (or modify the can, removing the ballast and rewiring it, which is probably not worth the effort).