CRM Outlook Client and Dynamics CRM Online 2015 with Server Side Sync

The other day we had a problem with the CRM and the Outlook synchronization, because the emails used in the Outlook and the login in the CRM “were different”.
In this case, a group of companies use the same office365 that has a unique domain, for instance “” and this is the domain used for login in CRM. On the other hand, the email that is used in Outlook is “”, this is because even the domain of the office365 is the same, there is a configuration at the Exchange level that since there are different companies and they want to use different outgoing emails (“”).
The emails sended to “” and “” are received in the same mailbox (“”).
When you have the users from office 365 and CRM, the domain name (login) and the primary email are the same …”” and an article of Microsoft says that the email address between office 365 and CRM must be the same.

Since the emails weren’t the same, the synchronization wasn’t made and the appointments, tasks, etc weren’t passed to the Outlook or vice-versa.
We were thinking that if we changed the primary email to the company email (“”) that might get it working but not knowing if it would do something wrong.
So we changed the email to the “”, made a test in one of the users and it was all ok, we had to change from the Server Side Sync to the Microsoft Outlook Client in the Email configuration.

Hope this helps!