The ERROR: wp_remote_get() function is blocked error means that the WordPress wp_remote_get() function is not able to check/GET the Apache Module test image files in this folder: /plugins/bulletproof-security/admin/mod-test/. Possible causes could be that the WordPress wp_remote_get() function is being blocked/not allowed by something either that you have installed on your site or maybe something your server is blocking or maybe a folder/file permission or folder/file Ownership issue/problem and the /mod-test/ folder and images cannot be retrieved for testing. If the Apache Module test fails then BPS will use the old mod_access_compat Order, Allow, Deny directives as a fallback. Try clicking the View Visual Test link and let me know what happens.
Also since this Apache Module test thing is brand new then there are other possible things that could occur. ie things we do not know about yet like something a particular host is doing that is different, etc.