nav-menus.php giving 404 error when editing specific menu

Hello,

I have a few menus on one of my sites on my wordpress multisite set up. recently i noticed when i try to go to edit one of the menus i set up, im taken to a 404 error page, saying that the page cant be found (A wordpress 404 page).

ive tried increasing the memory for the front end and administration pages. that didnt work

Ive tried to reset the permalinks. that didnt work

Any ideas?

the only other thing i know to do, is to make a brand new menu. but what if it happens again? i cant create a new menu every time.

thanks for the help in advance!