Cant add testers to my build

I can’t seem to add no one as testers or editors in my unpublished worlds .

i added some friends and it worked fine , couple days later I Cant add no one, I can’t even get into manage people tab because as soon as I click it , the menu crashes and and comes up with a error .

I also tried cloning the world and even in that new cloned world it’s the same thing . 
other worlds I’ve built seem to work fine