The particle is a thunder. It is on the right side.My issue is that the problem appeared suddenly.When I put it in my scene and played it for the first time,it was working.Suddenly I can only see it when I am in editor mode.I didnt change anything that has to do with postproccess, environmental fog. It just stopped working in play mode. I have some issues with the project folder at the moment and I have to update the whole project.So maybe it might fix.But if anyone else has something to suggest,please do so.