Lights won't reach the whole image (leaving a black border) and I don't know why

My lights won’t cover the whole object I’m shading!
There always seems to be a thin border that is no lighted, no matter what y do.
Here you have some images that show my problem:
It’s even more evident looking from the distance…

How can I get ride of this black line arround my light??

Here I’m showing a basic example and my node map:

I duplicated the nodes from this video and was able to get a glow on an ellipse without the lines being a factor. Comparing yours to this there is a slight difference in the nodes. I am not sure whether it is the source of the problem.

This second video goes into more complicated variations and results. Sometimes it helps to see what produces what effects in order to better understand simpler objectives.

I tried creating a blue ball with only colour vector lines (only the blue line) but the problem seems to keep reproducing.
Would you mind sending me a sample project with basic lighting so I can compare your settings to mine?

That would be due to the lines you are using. I am not sure how Harmony treats it but I would see whether it is sensitive to a line that includes a break with no visible line. Try drawing the object leaving a gap where you want the glow to reach the borders. Only use a line without a visible line in that gap. The exact term for a line that is not visible I cannot think of at the moment.

Thank you for updating us with the outcome YourTexasBenefits