Not receiving mail in yahoo.

[Technikalah nicmar]

Hi, 

      The form mailer works fine when it is used to send auto replies  to all other mail ids (google and others) but when the form registrant uses his yahoo mail id. It appears the mail is being sent from my gmail account linked with formmailer but the yahoo recipient is not receiving it in his inbox. I dont get why this is happening with only yahoo. Please help me solve this.