Forum Discussion
Tenant to Tenant Mail send as permission
Hi All, We are engaging a third party company who will be processing email requests on our behalf. The idea was to have a forwarder set to forward the support calls onto the third party and then ...
1) You can only connect a single e-mail domain to a single Office 365 tenant; a tertiary (sub)domain is perhaps more ideal, for sake of routing bulkmail and seperating mail flow.
2) That said, bulkmail is limited in 365 (there are limits in message sending/no. of recipients/etc). So, usability for your scenario depends on volume. If not, you (they) may need to look at 3rd parties.
More info in EOP limitations, see https://docs.microsoft.com/en-us/office365/servicedescriptions/exchange-online-protection-service-description/exchange-online-protection-limits