Received this response from zoho
Please find the IPs for our IMAP and SMTP servers below,
IMAP - 204.141.42.115
SMTP - 204.141.42.118
We would like to keep you informed that the IPs corresponding to the IMAP and SMTP servers are subject to change. Hence we request you to use the hostnames directly instead of using the IPs corresponding to them.
Also we would like to inform you that we have intentionally blocked the ping requests to our servers. Hence the packet loss. Instead of pinging the servers, you may run a OpenSSL test to check the connectivity.
I’ve already tried these IPs and unable to find a solution to set up email domain. Would really like to know a fix.