Around a month ago a site I manage... rainbowfx.co.uk started blocking google (403 error), It has only just been spotted as the site has dropped off of the rankings. I can't seem to find a way to fix this. the robots.txt file is fine, I have checked with the hosting company to see if it is anything they have done or can spot.
I have the site running through CloudFlare, I have tried deactivating that with no luck.
The next step was deactivating all plugins and google is still being blocked.
to add to the mystery the site had vanished from my webmasters tools account too