Why are the emails using the dedicated outbound IP addresses marked as SUSPECT/SPAM?
Dedicated Outbound IP Addresses (option available for purchase)
If you have purchased dedicated outbound IP addresses, it will need to be warmed up responsibly in order to maintain a Good Reputation.
Oracle B2C Cloud Operations can provide warm up using the email from the shared pool on your data center or you can warm up a new dedicated IP with your own traffic. This should be done by slowly injecting mail through those dedicated IPs with a consistent volume, starting with a low volume and gradually increasing the volume over time. Please see the attached document for guidance for warming a new dedicated IP. Oracle University offers a free course IP Warming Basics. Alternately Oracle provides consulting engagements for warm-up and ramp-up services.
It was also strongly recommended that you ensure that SPF and DKIM authentication be configured at the time as well, as this would help with the IP warm up and reputation in general.
Please see Answer ID 2489: SPF and Sender ID considerations with Oracle B2C Service sites where it explains that in both Sender-ID and SPF, a special TXT resource record associated with the domain name portion of an email address is queried in DNS. In the Sender-id and SPF records, you specify your email delivery policy. Neither Sender-ID nor SPF mandate what your email delivery policy is, they merely provide the tools to do so.
The receiving email servers configured to check for SPF will verify that the sending server is authorized according to the policy defined within the SPF and Sender-ID record for the sending domain name.
If your body FROM: (what you see in the email from field) domain is not an Oracle B2C Service assigned email address, your IT department will need to publish the SPF record in your DNS. Email messages that fail SPF or Sender-ID validation are much more likely to be regarded as Junk or Spam, and handled accordingly, such as being deleted, or moved to special Junk folders.
Therefore you must take care to ensure that all mailings use an email address that does have SPF and DKIM enabled for the sending domains.