User is not in the list and i cant add it . USER ALREADY EXIST

User is not in the list and i cant add it . USER ALREADY EXIST

Dear Support Forum ,

I have facing an issue for adding an user email address . but when i try to add this then it's showing "User already exist."


Please Solve this issue . i went to create this user pablo@sojohr.com but when i try to create then it's User already exist



Please Help Me 

Thank You