Different results when testing TLS with the help of CDN77

I've enabled TLS1.3 on three servers located behind another load balancing server on which TLS1.3 itself is enabled. I get different results if the domain name is written without www. All servers have active ssl certificates. Here are the results of the test during the test in the cdn77 controller:

I get "Excellent" if www.domain.com is tested. however,
I get "mediocre" in Firefox and "moderated" in Google Chrome if domain.com is tested without www.

I have no error regarding SSL when I test in gmetrics, pingdom, etc.
What do I miss in my setup