Outlook sometimes receives internal email with alias instead of display name

[jugalkumark]

One of the Users outlook receives internal emails sometime with display name like (Don, John) which is correct but sometime jDon@domain.co which is incorrect So what should i look for to fix this issue ?




i have tried and looked for the entry in the contacts but did not find those contacts and tried changing the address book view options from the address book (contacts folder) nothing changed any thing need to look from Exchange Server Side.