DKIM is an email authentication system that uses two cryptographic keys: a public key published in a Domain Name System TXT record and a private key encrypted in an outgoing message signature. The domain owner is the one who generates both keys. This way, it can be checked if the mail is authentic or forged.
Here is the procedure to enable DKIM authentication:
Go to your DNS and make the following changes in your DNS records
Create two CNAMEs (example.com is used as an example, replace your domain name with it)
And point them (1) and (2) to the following
If the CNAME cannot be created, please contact MailUp support for additional details
It takes 24-48 hours for changes to take effect.