Unable to update pages

Hello! I am having issues with updating the pages on my website: https://www.mymalaywedding.com

I got this error message every time i clicked on “Publish”: “This request has been denied for security reasons. If you believe this was in error, please contact support.”

I have updated all my plugins, themes (am using Sugar and Spice Child Theme) and am using the latest version of WordPress.

It is bizarre, I can add/change menus, widgets and posts, but I cant update my Pages section..any help would be appreciated! Thanks!