Hi Admins,
I have emails that are being routed to onpremise edge server( smarthost) from office 365 through connector for a specific domain.
I see from the Security and compliance reports that TLS is not being used, emails between office 365 and Edge server are/is unencrypted.
I try to force tls from office 365 outbound connector and validate it with both options, Using third party CA cert as well as any digital self signed cert.
It returns an error matching this.
450 4.4.317 Cannot connect to remote server [Message=451 5.7.3 STARTTLS is required to send mail] [LastAttemptedServerName=edge.domain.com] [LastAttemptedIP=165.xxx.xx.xx:25]
I have checked on the receive connector it is auth mechanism is set to use TLS.
We are good to go from firewall side, what more could i check? what logs to check for find out why TLS auth is failing? basically what and where to look for?
Any help will be appreciated.