ISE SMTP test connection not working

[NetworkMonkey101]

Hi, 

I have setup a office 365 SMTP server in ISE and the test connection is failing, states I need to import the trusted cert into ISE.

As far as I am aware I do not have this and should be downloaded from Microsoft.. cannot find details of the trusted cert anywhere online.

Can anyone assist?

Thank you

[Torbjørn]

Hi,

You can check which root CA the endpoint uses with the following openssl command:

openssl s_client -connect smtp.office365.com:587 -starttls smtp

Since you're using smtp.office365.com according to your screenshot you will need to add the Digicert Global Root CA certificate( https://cacerts.digicert.com/DigiCertGlobalRootCA.crt.pem) as a trusted root certificate: https://www.cisco.com/c/en/us/support/docs/security/identity-services-engine-software/200295-Install-a-3rd-party-CA-certificate-in-IS.html