MyBB Community Forums

Instead of going to inbox, how to correct this?

Not MyBB related. Contact Yahoo to find out why this is happening.

I think he is asking why his forum's mails are going in spam folders, probably host issue.

Yap, all my forum mail are sent to spam folder in yahoo mail.
But in gmail, its OK

That's a typical yahoo reaction to mails sent from mybb forums.
I simply disabled registration from yahoo addresses because mails to such users always end up bouncing or in their spam box.