Index param is not working in topbeat.yml

Hi :
i'm using topbeat 1.1.2, and i see the config param like this:

Optional index name. The default is "topbeat" and generates

# [topbeat-]YYYY.MM.DD keys.
# index: "topbeat"

after i change index param to my own name ,the topbeat can not send to ES any more, is this param work?
my config :
index: "machinelog"

any error message in topbeat? Can you try running topbeat in debug mode -v -d '*' ?

thanks for your reply, i try another name and it work now.