Face book is allowed but....

I have one user who is allowed to access social media. Every day I get a ticket complaining of social media being blocked. I have looked at it and she gets a "this page can not be displayed" error or the page loads as Text and is unusable. I have seen this error many times when forticlient is blocking a page it shouldn't. Now, this is where it gets wierd, By lunchtime facebook and twitter load and work. What can I check to try and resolve this?