We are launching a new website and we are sending the registration mail to users upon registration to activate their account. While testing we observe that our mails are landing in the spam folder of Yahoo and Gmail. This mail is a HTML mail and we have followed almost all guidelines regarding font-size, color, risky words, etc. Even Non-HTML also lands in the spam folder.
We have also set our SPF record and reverse DNS correctly.
Can someone guide as to what can be wrong because of which our mail consistently lands in SPAM folder of at least Yahoo and Gmail