user not found in client side people picker

Question

Hi all,

               I am using client side people picker in content editor webpart which is working perfectly in my development environment.

               In client environment its not working if we give the existing user in the people picker it shows as user not found, but the given user is the existing user of the office 365.no error messages in console too.

               The client side people picker is using in the office 365 environment.Any reference to find out what will be the issue. any help would be appreciated. Thanks in advance.