Configuration errors on subdomains

It’s a small thing, as I can easily ignore but for elegance, perhaps it could be addressed. For those website where the email is handled by a different server, rather than set up an email authentication for the contact forms I make a subdomain, usually forms.mydomain.com and then the from address becomes, legitimately, [email protected]. This triggers the WPCF7 error; Sender email address does not belong to the site domain.

Is it possible to adjust this so it allows subdomains as legitimate? (after all this is a different issue from a different domain)

Thanks for all the good work.