The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
@magge Thankyou for your response.
I restarted my computer twice. I also re-installed FAF. I also, checked my firewall 'allowed programmes list' as with all the updates something may have snagged on there. It now connects fine.
Thanks for your quick response.