Limited menu categories …

Hello,

I have created an e-commerce website using WordPress and the plugin of Woocommerce…. https://www.thefeedstore.co.uk

I have quite a lot of products and therefore a lot of product categories. However, when I add the product categories into the menu, wordpress deletes any category after the first 90.

I currently have 90 categories displayed in the menu. You will see that the last one is in Farm and is called Cattle & Calf, if I add any other product categories after this, it is deleted and does not show in the menu or in the back office.

Please can anyone advise me on what to do to get unlimited space in my menu?

Many Thanks!

Roz x