Can't save my lists!

Does anybody else have the same problem? I was editing couple of my list and all of the sudden I can’t save! I can’t save just one list, I am able to save all the others. Please, solve the problem!

One hour latter, I figure out I was accidentally trying to add name that was already on the list. I try to add another name, that wasn’t on the list and manage to save. Could adding same names (accidentally) cause some problems while saving?

Problem gone.