Please take a look at this (and similar) test:
https://www.ssllabs.com/ssltest/analyze.html?d=gpsoft.com.au
It seems the website is exposed to the Diffie-Hellman weakness. I hope you can update whatever needs to be updated, thanks.
Thanks, I've fixed this as far as I can tell.
(Click "Clear Cache" on the results if it still serves you the older ones.)
Thanks a lot for the quick response, indeed it is fixed. I noticed this because my browser (Pale Moon - stricter than mainstream browsers security-wise) wouldn't let me connect to the website.