Norton WiFi Privacy Help Please

Hello everyone

I visit schools with mobile planetariums and therefore get to connect to many different school wifi networks every month. I use a MacBook Pro Retina with OS X 10.11.6.

About 30% of the time my Norton WiFi Privacy connects successfully, without any problems.

About 30% of the time it fails to connect - but neither do my browser, Evernote and Dropbox - as the service is too insecure.

Yet about 40% of the time I obtain a good working connection with my browser and Evernote - but no connection with Dropbox and Norton WiFi Privacy. I find this very odd and would like to know why and if there is perhaps a solution?

Surely if Google, GMail and Evernote are happy with the level of security, then why is Norton WiFi Privacy unhappy?

Is there something I can do to help / force Norton WiFi Privacy connect?

Any guidance would be greatly appreciated.

Thanks very much