Hi!
It is a known issue affecting the current release (4.10.5). There is a temporary fix with a small code snippet. Try placing this code to the functions.php file in your theme directory (copy from line 3):
IMPORTANT: Before making any direct changes in your site files, please make sure you have a back-up of everything. To edit the files, I highly recommend using an (s)FTP client, instead of the internal file editor in WordPress – as any tiny mistake there can potentially lead to a site error.
If you need any help with placing this code, you can add FTP details at any time, and I will do it for you.
I hope this helps!