finished basement ceiling leak

There is a leak in the basement ceiling. The basement is finished. the drip is about 20 seconds apart. half bathroom is above but I checked and there is no visible water damage around the water pipes. see picture attached. It's hard to see due to the central air ducts and steel beams. any guess on what the problem might be?
Thank you!

Does it leak all of the time, even when no one has used, or is using, the bathroom?

If so, look at all of your supply pipes, including any flex lines leading to the toilet and sink. Dry them well, and then feel all of them, especially the connections.

If it only leaks when someone is using the bathroom, check one fixture at a time. Have someone flush the toilet while you look from the basement. If that is not it, run water in the sink and agaun, check under the sink and in the basement. Do the same for the tub.