Emails not delivering to yahoo email id's from zohomail account

Emails not delivering to yahoo email id's from zohomail account

I am trying to send emails to one of my client's yahoo email id.But the emails not delivering and displays the below message.
4.7.0 [TSS04] Messages from 103.117.158.52 temporarily deferred due to user complaints - 4.16.55.1; see

Can you explain why i am receiving this?