office 365

Have you setup the users in Office 365 admin center?

https://support.office.com/en-us/article/Understanding-Office-365-identity-and-Azure-Active-Directory-06a189e7-5ec6-4af2-94bf-a22ea225a7a9

As pler snapshot, you are using zujicorp.onmicrosoft.com as domain name to login while your users should use mail id in following format: userid@domain.com

Try then after.

Reasons to happen this

(1) Are these 3 users in different OUs? If no then its fine and if yes then check that should be synchronized with Azure AD.

(2) Have you checked in office 365 web portal ? Are these users showing the "Sync with Active Directory". If it is not then they are still not synchronized. Perform full synchronization using command    Start-ADSyncSyncCycle -PolicyType Initial

(3) If they are in different OUs then set the password synchronization more frequent.  check this website to do it

https://www.codetwo.com/admins-blog/how-to-sync-on-premises-active-directory-to-azure-active-directory-with-azure-ad-connect/

one more thing, if account is synced from AD but its cloud logon name is .onmicrosoft.com (user@yourdomain.onmicrosoft.com) instead of user@youraccepteddomain.com, still it won't accept AD password as it is considered as mismatch
you need to ensure that onpremise user UPN / email attributes are same and then sync again and then it will accept AD password