pls i tried implementing the PHP mailer library with using my webmail credentials, but on delivering to the clients(Gmail) it displayed a yellow warning alert indicating the google couldn't cerify of the message is actually from the Domain, stating the message isn't authenticated, Ive tried various solutions online but all to no avail and also the DKIM and SPF configuration indicated that they are all valid, Pls how do i fix this

I've tried to configure the DKIM and SPF but it has already been configured by my network provide(Host), stil the message still displays the yellow warning sign that the mail is not authenticated