The day we had a power outage, we also noticed that one bank of recessed lights stopped working. (Assuming they are related, but can't be 100% sure.) The lights are on a dimmer switch. I confirmed power at the switch, and that the switch is working (by swapping in another switch).
My next thought was to check the power and connections at the light closest to the switch. Assuming that makes sense, I can't figure out how to undo the clips that would allow me to slide the housing and junction box out (photo below). I've watched plenty of videos on how to engage the clips, but not undo them. I've tried using needle nosed pliers in the circular hole and pulling with quite a bit of force down and in, but so far it's just bent the black clip and silver housing. In case it's useful, the lights are L7XR Lithonia. These lights are between floors, so I have no access from above.
Thoughts are appreciated!
UPDATE: As one more last-ditch test, I swapped out the dimmer for a simple switch, and lo and behold, the lights turned on! The mystery is that I know the dimmer is fine because it works on a separate set of lights (and before that it was functioning fine for 3+ years on the lights in question). I'm okay with just using the simple switch, but I am curious about what could be the cause of what I'm seeing. Any more thoughts?