Cleaner used to fix the prob;em????

Question

There was something that didn't make sense to me, When I put the STP fuel system cleaner in it(silver bottle), it used to shut my check engine light off. I guess the issue has gotten so severe it doesn't work anymore. Are there any specific guesses there, or would you still recommend what you mentioned before. Sorry for all the questions, im a chick, and learning slowly but surley. Thanks a Bunch!