Dynamics 365 On-Premise
Setup Dynamics CRM E-mail Router with Office 365
Setting up the Dynamics CRM E-mail Router can be a bit tricky considering access rights to the Office 365 accounts. The long story short is that one account must be designated as the account through which all E-mail will pass. This means that account must have something called “Send As” privileges to the other Office 365 E-mail accounts. You can also use an access type called “Send On Behalf Of” but the difference lies in what the recipient sees:
If “Send As” is the method then the recipient just sees a normal E-mail address: user@company.com
If the “Send On Behalf Of” is the method then the recipient sees the routing account with a message that it is sent on behalf of: emailrouter@company.com “Sent on Behalf of: user@company.com”
As such, most people prefer to use the “Send As” option. This is how you setup a routing account with “Send As” privileges.