Anti-Cheat error??

invalid@example.com (Diamond12), Diamond12
Wed, 10 Jun 2020 10:36:18 +0000

Hello I was just playing vortexpvp prisons I was mining and all of a sudden I get a message that I was "Cheating" now I never hack on servers so I was confused by that. The only mod I have with me is Optifine. I thought I took a screenshot but I couldn't find it.