Email authentication

simonbrdly

The emails I receive notifying forum posts usually have Google Spam Protection notices slapped on them, and are stated as 'not authenticated'.
Google provide a step-by-step way to authenticate emails here: https://support.google.com/mail/answer/180707?visit_id=637855221003293863-2781195988&p=email_auth&hl=en-GB&rd=1#zippy=,a-message-that-ive-received-hasnt-been-authenticated
Is it possible for this to be done for the forum on behalf of the posters?
Sorry if this has already been raised, but I couldn't find anything here.
Simon