Cannot add user to existing SharePoint list

Question

I have a list with 3 columns - Person column, Text Column and Choice column. When I try to add a new item into the list, I start typing the person's name, the search box finds it, i click Enter, but it says This field cannot be left empty. When I try to add myself, it proceeds without any problems.

Answer 1

Type in user's email and edit list item in different ways to compare the result.

Create a new list with people column to check if the issue still exists.