I installed Wordfence (basic) on 9 sites this week, spread over 6 different hosting companies. On 8 sites it works perfectly. However, on one site, which is on a separate hosting company by itself, it blocks me from logging in no matter what I do. And, it reverts back to the default settings no matter what I set and save. Using WP 3.4.2. The only difference I can find is the theme I am using which is "Resizable" by Theme Junkie.
On the top of the Wordfence options page, under Basic settings, I set it to Medium protection and click save, says it is saved. Then I go to the lower Advanced portion and set all the settings (which are exactly the same as I have set them on the other 8 sites) and click Save. As soon as I click Save on the lower Advanced portion, the upper portion reverts back to "Custom Settings" instead of "Medium". As soon as I change it back to Medium and click Save, the lower portion reverts back to the default settings. It just goes around in circles. As soon as I click Save on one portion, the other portion reverts back the way it was before.
I have put my IP in the Whitelist section, and my IP and Username to ignore, but as soon as I log out of WordPress I am locked out again. I have to go into cpanel and delete the plugin. Then I clear temp. files, cookies, etc., and try again. But I have re-installed at least 5 times now, and it is the same every single time. It simply will not work on that site. The settings I put in will not save, even though it says they are being saved. And I am locked out no matter how many times I change the settings to allow my IP.
I am not using any different plugins than on the other sites where Wordfence works, and the same version of WP. The only difference is the Resizable theme, which I am not using on any other site. So I am not saying it is definitely the fault of the theme, because I don't know that for sure, just that it is the only difference I am aware of.