sub categories not saving to menu

Hello
I have a bog issue that seems to be them related.
I am trying to add new sub categories (product categories) to my menu. However, when I hit the save button, they don't save.
In fact, wehen trying to add a new sub category, it deleted a lot of other subcategories so now on my website, a lot of product categories are missing from my top menu (when you hover over it).
They are not saving to menu when I tried to put them back in.

(FYI: my host has put the number of max_input_vars up to 3000.)

Can anyone advise me what to do? Thanks

Hi,

Could you please provide me with a URL to your website and back-end access via PM (click the “Private Message” text underneath my avatar) so that I may analyze it?