New custom menu item and widgets won't save

[LeighaBaer]

Hello
I am working on a site for a client, and we've customized the Allure theme. I'm having the same issue in two areas of the theme: custom menu and widgets - I go to create a new custom menu link and/or to add a new text widget and click 'save' and it just hangs up, looking like it's saving, but it never actually does.

I have added the ability to use custom menus to this theme and have added several pages successfully. I have also added other text widgets to this site successfully, but when I go to add a new one, it just sits there, looking like it's saving, but never does.

My internet is up and running fine, the server is running fine - so not sure what could be causing this. Not sure why it's now doing this - anyone else have this issue?