Receiving recommendation letters after graduation I am applying for a few different masters' programs and I need three recommendation letters total. I graduated from university last year spring, and when I send emails to the professors I had for my major courses, the majority of them do not respond (they responded when I was a student on campus).


Are professors more likely to ignore emails from students who are no
longer affiliated with the school?
Also, is it fine to accept recommendation letters from professors who taught courses that I received my minor in?
Are professors more likely to ignore students who are no longer
  affiliated with the school?


They often show the tendency for presenting the recommendation for the students, who had a live impact in their minds in view of academic performance, personality and so on. You can't expect from a professor to write anything useful about you, when he/she even can't recall you, deservedly.

On the other hand, leaving the academia and the school, within which the professor is affiliated, would not lead to his/her certain ignorance. In my own explicit experience, one my professors did present an awesome LoR for me, even though I'd left the department for more than 3 years. He did that with due attention to our constant communication and collaborating on some research stuffs.


  is it fine to accept recommendation letters from professors who taught
  courses that I received my minor in?


Yes. The recommendation should come from the person, who can depict you, as well as possible. The lecturer of a minor course, could who be able to hit this mark, would be a right choice.