Google Groups not responsive on smartphones

Hi,
I’ve installed the plugin in order to embed our Google Group “forum” in our WordPress site. All is well functioning on PC, but using smartphones (checked on iPhone and Android) the page is no more responsive.

If you’d like to check it this is the link: http://mib-trieste.it/forum/

Thanks a lot for your work!

https://wordpress.org/plugins/sz-google/