Updating the DKIM Security Key
Article ID: 220970
Updating the DKIM key, which currently has only 1024 bits to 2048 bits.
Release : 10.7.4
Create a new DKIM key with 2048 bits. (Administration > Certificates > DKIM)
Adding a domain key
Select the new DKIM key and generate a new DNS record. (Protocols > Domains > Select the Domain > Delivery)
DO NOT SAVE prior to performing step #3.
You can reference the DKIM section of this document for more information:
Setting up sender authentication for outbound mail
Update the DKIM DNS record in the public DNS record for the domain with the new key.
Select the new DKIM key and Save. (Protocols > Domains > Select the Domain > Delivery)