Macbook said: unity could not connect to debugger

Hi all developers! Please advise me what I'm doing incorrectly. I would like to set a trap in the code and inspect the values of variables. I've seen others do it in the movies youtube. You have to select the lines and click then there is a large red dot. For me, unfortunately, it is different. Instead of dots are three circles of pale red and the program in these places does not stop. If enforces run to get the message: could not connect to debugger. What to do? thanks for the tips and best regards!