Can't save menu items

I’ve searched the forum but cannot find a solution to this issue. I’ve looked outside of this forum and see repeatedly the idea of having the hosting company edit a .php file, but I want to know if there’s another way.

I have multiple menu items, well over 40, and I can’t save any more to the menu. After clicking ‘save menu’, the new items simply disappear.

I know it’s not a browser issue as I’ve already tested that.

This is very inconvenient and puts a wrench in project time.

What is WordPress’ solution to this?