From Dynamics CRM 8.2 (Online) using Admin account, we are sending Email to users. Most of the users do receive Emails but only 3-4 users do not receive Emails.
1. Email are in Sent Status from Crm
2. When checked Mailbox of Admin, Emails to there 3-4 users are Bounced back.
3. Error Stated as "Remote Server returned '420 4.2.0 Recipient deferred because there is no Mdb"
4. Users use IBM Lotus Notes as Email application
5. Users do not have mailbox on Office365, Only Admin does and hence Admin can send Email