I tried searching this but there has been no answer. When I make any change to my websites menu bar (nav-menu) it lets me edit but then when I hit “save” it sends me to a page not found 404 error. ( ExampleWEBSITE.com/wp-admin/nav-menus.php) is the page it returns, but says 404 error. I have tried uninstalling all plugins, re-installed wordpress, I have done everything I can think of. I would really appreciate any help. Thank you!