Hello There,
Thanks for writing in! This could be a 3rd party plugin conflict. You could try testing for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
I also noticed that you are using an older version of X. X 5.1.1 is now available. Please update to the latest version. After doing the updates, if you have installed caching plugin, please clear the plugin cache first before testing your site.
We would loved to know if this has work for you. Thank you.