like pic below, sometimes it's go away sometime it's back. 

All lights are in good shape, no problems at least from what I can see.

What can be a reason for this warning to come up?

thanks

 

one of them's about to fail.

I had this last week. Warning light on and all bulbs working. Took all rear bulbs out one at a time and found that one of the stop and tail (twin filament) bulbs the glass was a little smoky but still working. I changed the bulb and not had the light on since.

also worth noting it does power up other lights to replace brake lights and tail lights etc. so double check all of them are working

Remember to check rear number plate lights as well, they can cause the error

also worth noting it does power up other lights to replace brake lights and tail lights etc. so double check all of them are working

 

Not on the Octavia...