keeping entity minecraft : cow that already exists with uuid 5bffble53c2-453f-9060-d75739d26cb8 how to fix

the screen shot i provided shows i get this message "keeping entity minecraft : cow that already exists with uuid 5bffble53c2-453f-9060-d75739d26cb8" and it crashes my server and i can not log in to server to do anything is there a way to fix through the server console?