I lag out constantly on a multiplayer server

I can play fine, for the most part, I just randomly get block lag, which is either due to the error, or the servers lag, but I can't tell which, I lag out and can't get back to the server for a few minutes. I have two accounts and I think that may be the problem, the server has MCMMO stats and it lists both my accounts' stats in one place, which I think it can't handle, but I'm not sure how to fix this at all. Can I get some help on this please, it just happened again.