Primary Contact greyed out for everybody

Hi Everybody,
we are using and loving ERPNext and learning everyday, customizing and really develop.
Today i faced the first time a problem i can’t solve by myself. Maybe you can help me.
When creating customers suddenly the Primary Contact fields are grey out and not useable anymore. Since Email is a mandetory field, we cant creat new customers. Its obv the same in the full form as well. Does anyone have an idea how to solve this problem?

I think the problem is here. But I cant change it to somethingelse than Read Only. It worked before, so i am a little confused, what is going on.