our ERP server is On-Prem and Email is getting sent through on-prem exchange server which we are planning to decommission as all mailboxes are on office 365. ERP team suggested to add a connector on Office 365 to whitelist IP sending out email.  We did that and updated our SPF record as well.  Still emails are not getting sent and ERP team is asking to have PORT 25 open to send out emails.  I did telnet from the Exchange server on port 25 and also the whitelisted IP on port 25 everything works fine. While doing telnet smtp.office365.com on port 25 - it fails.     How do we fix this? ... View more