I am a seasonal web developer. I also resell hosting services to some of my clients. Recently, all the emails sent from my client’s hosting accounts to Yahoo Mail end up in Spam directory. They were fine before (email delivered to in-box), the problem just happens recently and it happens to all of my client’s hosting accounts.
I have contacted the web hosting provider ( scalahosting ) and they said the problem is with yahoo, their server is fine, and the problem just happen to me, no one else has complained except me.
