So I wasn’t able to add new items to wordpress menu and found out that the reason is the POST limit but adding max_input_vars = 2000 did not solve the problem (default is 1000). If you have suhosin and cant add new menu items or save your menu, you have to add the below to your php.ini:

max_input_vars = 2000
suhosin.request.max_vars = 2000 = 2000