Akismet 3.0 isn't working

After updating WordPress to 3.9, the plug-in Akismet is no longer working on one of my client’s sites. I have uninstalled the plugin, reinstalled it, and its still not working. Any ideas? I have over 6 wordpress client sites and this is the only one with the problem. It is on a different server than the others, so like the notice says, I contacted my web host, but they had no answers for me.

Any help would be apprecaited