If you are using Facebook’s Like Box, you should be aware that they are making changes to the API which will cause the Like Box to no longer work on June 23, 2015.
Facebook is suggesting that webmasters use the newer Page Plugin instead, but you will need to remove the old code before you can activate this new plugin. The new plugin also offers the ability to display content from the Facebook Page as well as display the Facebook Page’s cover and friends who have liked it. Here is an example of what it looks like:
Many WordPress plugins use the Like Box that is being deprecated, so you will need to ensure they have been updated to take the change into account or they could stop working or display errors.