iDRAC CA Certificates and new CAs

Dear All,

in our infrastructure we just activated an internal SMTP server with authenticated SMTP with SSL and STARTTLS mandatory.

I just set the new SMTP Server in iDRAC 9 but I am unable to send emails.

The error is "RAC0225: Sending the test mail failed"

The SSL certificate we are using in the SMTP Server is a regularly bought certificate from an official Certification Authority (Actalis), but it turned out that their latest intermediate CA (Actalis Domain Validation Server CA G3) is not trusted in most of the Truststores, as it is very recent (july 2020).

So I think that iDRAC 9 is refusing to send e-mails with this new SMTP Server due to the unrecognized CA that emitted the SSL certificate.

Is it possible to add this Intermediate CA to the truststore inside the iDRAC?

Or: is it possible to force iDRAC ignore certificate verification when sending emails?