“DKIM authentication settings update failed” is a common error that may occur because your email provider is likely having a problem with their DNS records or authentication servers.

DKIM key rotation is the process of updating your DKIM keys. You should rotate your keys periodically—the exact period isn't important, but the process itself is. It's a security measure that helps prevent attackers from impersonating your domain.

Meta: While DMARC protects you from a wide range of cyberattacks, it is no silver bullet. Here is a full list of which attacks does DMARC not protect you from!