wordpress menu problem !!

I really need help. I use this theme https://www.bkmotomasyon.com.tr/ and my problem is that when I add links to the second menubar, using the wp menu maker, it seems to me that I only can add 90 pages/links all together. When I have reached 90, I cannot add more linkes. Please help me, it is very important to solve this for me. I cannot finnish my work before I have solved this