من ایمیل هام میرفت به اسپم یاهو آخر هم ایپی و دامینم بلاک شد (واسه باز کردن کسی اگه میتونه کمک کنه )
من به پشتیبانه whmcs گفتم اینا همه میره به اسپم اینو گفت حالا یکی ترجمه کنه ببینیم چیه
What method of sending mail are you using php or smtp. You can check this here > Setup > General Settings > Mail tab
This issue with free service providers is very common and is not a whmcs issue you need to make sure you have RDNS, SPF configured correctly and also be part of the msn safe sender program to get mail placed in inboxes. Also need to verify Yahoo and MSN has not labeled your server as a bulk transporter. If MSN is the issue, then try using this form: http://www.microsoft.com/senderid/wizard
Also will need to incorporate domain keys on your server for yahoo mail.