I'm not sure what you're trying to ask here. Send "inbox" emails in yahoo"?? Are you sending emails from your yahoo account to someone and it goes into their spam folder?

Have you tried other email accounts besides yahoo?

inbox depends on a lot of factors, IP/Domain/URL reputation. From Name/Email reputation.
message contents & message structure.

Should follow "Can Spam Act" and also your emails content, subject, IP/domain also important to send emails into the inbox.

There are many different reason why you might not be inboxing in Yahoo. Have you sent a test email to mailtest@unlocktheinbox.com to make sure your configuration is correct?