Menu Saving Problem

I have started to experience an issue that I cannot seem to fix so I am reaching out to the community here for help. It appears when I try to add a new item to my MENU and then click SAVE CHANGES, I am taken to a blank white screen. Sourcing the screen shows nothing. When I try to go back to edit the MENU again, the changes I attempted to make are gone. The only thing I have recently changed is that I installed a new theme that allows the use of two MENUs. This is important to note as the items I am trying to add and save to MENU 1 always fail but I was able to add those items to MENU 2. If it would help to record a screen cap, please let me know and I will post one up right away. Thanks in advance.