VBR e-mail settings to O365 (check certificate)

[BostjanUNIJA]

Hi.
- On firewall level we have closed outbound connection from VBR to WAN.
- We have created exceptions for typical SMTP ports: 587, 25 for outbound traffic.
- We have created exceptions HTTPS outbound rule only for specific domains: *.microsoft, *.office365.com, *.veeam.com
- SMTP server is set as: smtp.office365.com
- Test messages is sucessfully.

But when we confirm e-mail settings a pop for checking certificate is shown.
I'm guessing that we must create allow outbound rule also to some CRL's because above check doesn't pass?
Any ideas.
Thank you.

[Mildur]

Hello Bostjan

Which version of Veeam Backup & Replication is currently running on your system?
There were cases in the initial v12 builds where users encountered certificate errors while testing SMTP. This should be solved by now (most recent patch of v12, v12.1).

Another question If I may:
Why are you not using the Microsoft 365 OAuth 2.0 to send the mails?

Best,
Fabian

[BostjanUNIJA]

Hi, thank you for your reply.

- V12: 12.0.0.1420 P20230718 build.
- don't feel 'confident enought' to upgrade to 12.1 as I see several issues (topic on Veeam forum), that people are dealing with issues (will wait for 1 month...)
- 365 oAut 2.0. - good question; haven't transfered to that type of mail releay yet.