Structured Data Fault

I posted 2 reviews and when added shortcode to the footer it is displaying reviews ok but when tested with Structured Data Testing Tool it come up with this fault.

Failed to normalise the rating value.
Your rating value was out of the default range, you must provide best and worst values.

please see screenshot
https://www.dropbox.com/s/yhc29hb5rmtnayy/Untitled.png?dl=0
(just close the login box to see screenshot)

Also if i click to see single post with reviews activated — all is fine however when I display same post on homepage all is gone and only blank post displayed.

Any help please ?

https://wordpress.org/plugins/wp-customer-reviews/