Here are some common reasons why users find that nothing is being blocked:

• They didn’t enter a list of sites to be blocked.
• They included URL protocol prefixes such as http:// or file:// in their list of sites (see Note under the text box!).
• They didn’t enter either a time period within which the sites should be blocked or a time limit after which the sites should be blocked.
• They selected within time periods AND after time limit but did not enter both a time period and a time limit. (See here for further explanation.)
• They didn’t select any days on which the sites should be blocked.
• They added keywords to the list of sites, but did not understand how keyword blocking works.