Banned for Third Party

Hi, I recently tried logging into my League of Legends account and I received a message saying that I was banned for using a Third Party system. I don't understand because I've been playing League for years now on that same account. In addition, I only play about less than 10 games per week. The only "Third Party" systems I can think of is the Twitch/Curse app and Discord app. I also recently downloaded a new security software on my laptop. If I could get some insight on what I can do, it would be very much appreciated. Thank you.