@Silentfriend
I obviously can't know what your circumstances are but as others have said, sometimes the reasons for the change in the friendship are based on a very wide range of characteristics of both friends, rather than one simple action. So no fallout.
I have stopped contacting and putting in the effort with 2 friends over the years. Neither of them had done anything wrong, but friendships evolve and sometimes a person's way of being, their priorities in life become clearer as they grow and you see that not only do they not align with your own, they also make you feel worse about yourself, even if that was never intentional.
I could never tell my friend for instance, that the way she is, both simultaneously irritates me and creates insecurities in me. It's not a small aspect of her character, but a fundamental part of it.
Even though I know that she is a loving person the way she is means that even when we do speak I will feel down and drained afterwards without her having said or done anything awful. I can't tell her that even listening to her every day life and the way she tells me leaves me stressed out.
I suppose the most important part is that she actually is a good person, but I can't be friends with her without feeling bad about myself, and she can't be friends with me because she decides to fill her life so very much with work and children's activities that she has no free time for a spontaneous chat.
We are not compatible, so aren't really friends anymore even though I still think she's a good person.