Hello, we became aware today that emails to Yahoo are being rejected. The error response reads the following:

xxxxxxx@yahoo.com, ERROR_CODE :553, ERROR_CODE :5.7.2 [TSS09] All messages from 136.143.188.53 will be permanently deferred; Retrying will NOT succeed. See https://help.yahoo.com/kb/postmaster/SLN3436.html

In looking at blacklists, this IP does not appear to be listed, but yet all emails to Yahoo.com email accounts are being rejected. Can you folks work with them to get this resolved?

Thank you