Unauthenticated mail [fix]

When I was testing my mailing system.It worked fine.

But,Gmail said My mail is not authenticated and I might be a spammer.

When I click on the avatar.It showed

I did Some research and caught up on dkim.And I found that it’s not that safe to use that dkim method.

I invested more time in it and found updating dns server aka spf record can fix that.

Now,my mail avatar is fixed and that unauthenticated message is gone.