I have observed in the past months a rather worrying trend for my bots. I am trying to figure out if I am doing something wrong or something else changed, i.e. Chrome web get text takes longer, UIRobot is now too busy from too many pending jobs, etc. Sometimes I observe the robot running (that green icon in my bar) but nothing is happening.
I would say that the time to get some text from web almost doubled from where it was some months ago. The scripts are exactly the same. I am using UiPath community edition.
Probably you reach the limits of logs and queue items. Try to refresh you queues. I had similar issue (link below) I had the same symptoms, robots work slower etc.